Charging system and method, and power adapter

ABSTRACT

The present disclosure discloses a charging system and method, and a power adapter. The system includes a power adapter and a terminal. The power adapter includes a first rectifier, a switch unit, a transformer, a synthesizing unit, a sampling unit, and a control unit. The control unit outputs a control signal to the switch unit, and adjusts a duty ratio of the control signal according to a current sampling value and/or a voltage sampling value, such that a second alternating current outputted by the synthesizing unit meets a charging requirement. The terminal includes a battery.

CROSS REFERENCE TO RELATED APPLICATIONS

This U.S. application is a Continuation of U.S. application Ser. No.15/657,377, which is a Continuation-in-Part of International ApplicationNo. PCT/CN2016/073679 filed Feb. 5, 2016. Application Ser. No.15/657,377 also claims priority and benefits of Chinese Application No.201610600611.9, filed Jul. 26, 2016. The entire contents of each of theaforementioned applications are incorporated by reference as part of thedisclosure of this U.S. application.

TECHNICAL FIELD

The present disclosure generally relates to a terminal technical field,and more particularly, to a charging system, a charging method, and apower adapter.

BACKGROUND

Nowadays, mobile terminals such as smart phones are favored by more andmore consumers. However, the mobile terminal consumes large powerenergy, and needs to be charged frequently.

Typically, the mobile terminal is charged by a power adapter. The poweradapter generally includes a primary rectifier circuit, a primary filtercircuit, a transformer, a secondary rectifier circuit, a secondaryfilter circuit and a control circuit, such that the power adapterconverts the input alternating current of 220V into a stable and lowvoltage direct current (for example, 5V) suitable for requirements ofthe mobile terminal, and provides the direct current to a powermanagement device and a battery of the mobile terminal, therebyrealizing charging the mobile terminal.

However, with the increasing of the power of the power adapter, forexample, from 5 W to larger power such as 10 W, 15 W, 25 W, it needsmore electronic elements capable of bearing large power and realizingbetter control for adaptation, which not only increases a size of thepower adapter, but also increases a production cost and manufacturedifficulty of the power adapter.

SUMMARY

Embodiments of the present disclosure provide a charging system. Thecharging system includes: a battery; a first rectifier, configured torectify an input first alternating current and output a first voltagewith a first pulsating waveform; a switch unit, configured to modulatethe first voltage according to a control signal and output a modulatedfirst voltage; a transformer, having a primary winding, a plurality ofsecondary windings, and an auxiliary winding, and configured to output aplurality of voltages with pulsating waveforms via the plurality ofsecondary windings according to the modulated first voltage, and tocouple the modulated first voltage via the auxiliary winding; asynthesizing unit, configured to synthesize the plurality of voltages tooutput a second alternating current, in which, for each cycle of thesecond alternating current, an absolute value of a peak voltage of apositive half is greater than that of a trough voltage of a negativehalf, and the second alternating current is configured to charge thebattery; a sampling unit, configured to sample voltage and/or current atthe auxiliary winding to obtain a voltage sampling value and/or acurrent sampling value; and a control unit, coupled to the sampling unitand the switch unit respectively, and configured to output the controlsignal to the switch unit, to adjust a duty ratio of the control signalaccording to the current sampling value and/or the voltage samplingvalue, such that the second alternating current meets a chargingrequirement of the battery.

Embodiments of the present disclosure provide a power adapter. The poweradapter includes: a first rectifier, configured to rectify an inputfirst alternating current and output a first voltage with a firstpulsating waveform; a switch unit, configured to modulate the firstvoltage according to a control signal and output a modulated firstvoltage; a transformer, having a primary winding, a plurality ofsecondary windings, and an auxiliary winding, and configured to output aplurality of voltages with pulsating waveforms via the plurality ofsecondary windings according to the modulated first voltage, and tocouple the modulated first voltage via the auxiliary winding; asynthesizing unit, configured to synthesize the plurality of voltages tooutput a second alternating current, in which, for each cycle of thesecond alternating current, an absolute value of a peak voltage of apositive half is greater than that of a trough voltage of a negativehalf, and the second alternating current is configured to be introducedinto a terminal to charge a battery of the terminal when the poweradapter is coupled to the terminal; a sampling unit, configured tosample voltage and/or current at the auxiliary winding to obtain avoltage sampling value and/or a current sampling value; and a controlunit, coupled to the sampling unit and the switch unit respectively, andconfigured to output the control signal to the switch unit, and toadjust a duty ratio of the control signal according to the currentsampling value and/or the voltage sampling value, such that the secondalternating current meets a charging requirement of the terminal.

Embodiments of the present disclosure provide a charging method. Thecharging method includes performing a first rectification on an inputfirst alternating current to output a first voltage with a firstpulsating waveform; modulating the first voltage by controlling a switchunit, and outputting a plurality of voltages with pulsating waveforms bya conversion of a transformer; synthesizing the plurality of voltages tooutput a second alternating current, in which, for each cycle of thesecond alternating current, an absolute value of a peak voltage of apositive half is greater than that of a trough voltage of a negativehalf; applying the second alternating current to a battery; coupling aprimary output of the transformer via an auxiliary winding of thetransformer, and sampling voltage and/or current at the auxiliarywinding to obtain a voltage sampling value and/or a current samplingvalue; and adjusting a duty ratio of a control signal for controllingthe switch unit according to the voltage sampling value and/or thecurrent sampling value, such that the second alternating current meets acharging requirement.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram illustrating a charging system accordingto embodiments of the present disclosure.

FIG. 2 is a schematic diagram illustrating a synthesizing unit accordingto an embodiment of the present disclosure.

FIG. 3 is a schematic diagram illustrating a synthesizing unit accordingto another embodiment of the present disclosure.

FIG. 4 is a schematic diagram illustrating a waveform of a chargingvoltage outputted to a battery from a power adapter according to anembodiment of the present disclosure.

FIG. 5 is a schematic diagram illustrating a control signal outputted toa switch unit according to an embodiment of the present disclosure.

FIG. 6 is a schematic diagram illustrating a fast charging processaccording to an embodiment of the present disclosure.

FIG. 7 is a schematic diagram illustrating a charging system accordingto an embodiment of the present disclosure.

FIG. 8 is a schematic diagram illustrating a charging system accordingto another embodiment of the present disclosure.

FIG. 9 is a schematic diagram illustrating a charging system accordingto yet another embodiment of the present disclosure.

FIG. 10 is a block diagram of a sampling unit according to an embodimentof the present disclosure.

FIG. 11 is a schematic diagram illustrating a charging system accordingto still yet another embodiment of the present disclosure.

FIG. 12 is a schematic diagram illustrating a terminal according to anembodiment of the present disclosure.

FIG. 13 is a schematic diagram illustrating a terminal according toanother embodiment of the present disclosure.

FIG. 14 is a flow chart of a charging method according to embodiments ofthe present disclosure.

FIG. 15 is a block diagram of a charging device according to embodimentsof the present disclosure.

FIG. 16 is a block diagram of a power adapter according to an embodimentof the present disclosure.

FIG. 17 is a block diagram of a terminal according to an embodiment ofthe present disclosure.

DETAILED DESCRIPTION

Descriptions will be made in detail to embodiments of the presentdisclosure, examples of which are illustrated in drawings, in which thesame or similar elements and the elements having same or similarfunctions are denoted by like reference numerals throughout thedescriptions. The embodiments described herein with reference todrawings are explanatory, are intended to understand the presentdisclosure, and are not construed to limit the present disclosure.

The present disclosure is made based on the following understanding andresearches.

The inventors find that, during a charging to a battery of a mobileterminal by a power adapter, with the increasing of power of the poweradapter, it is easy to cause an increase in polarization resistance ofthe battery and temperature of the battery, thus reducing a service lifeof the battery, and affecting a reliability and a safety of the battery.

Moreover, most devices cannot work directly with alternating currentwhen the power is usually supplied with the alternating current, becausethe alternating current such as mains supply of 220V and 50 Hz outputselectric energy discontinuously. In order to avoid the discontinuity, itneeds to use an electrolytic condenser to store the electric energy,such that when the power supply is in the trough period, it is possibleto depend on the electric energy stored in the electrolytic condenser toensure a continue and stable power supply. Thus, when an alternatingcurrent power source charges the mobile terminal via the power adapter,the alternating current such as the alternating current of 220V providedby the alternating current power source is converted into stable directcurrent, and the stable direct current is provided to the mobileterminal. However, the power adapter charges the battery in the mobileterminal so as to supply power to the mobile terminal indirectly, andthe continuity of power supply can be guaranteed by the battery, suchthat it is unnecessary for the power adapter to output stable andcontinue direct current when charging the battery.

In the following, a charging system, and a power adapter provided inembodiments of the present disclosure will be described with referenceto drawings.

Referring to FIGS. 1-13, the charging system for the terminal providedin embodiments of the present disclosure includes a power adapter 1 anda terminal 2.

As illustrated in FIG. 1, the power adapter 1 includes a first rectifier101, a switch unit 102, a transformer 103, a synthesizing unit 104, asampling unit 106, and a control unit 107. The first rectifier 101 isconfigured to rectify an input first alternating current (AC for short,mains supply, for example AC 220V) to output a first voltage with afirst pulsating waveform, for example a voltage with a steamed bunwaveform. The first rectifier 101 may be a full-bridge rectifier formedof four diodes. The switch unit 102 is configured to modulate the firstvoltage with the first pulsating waveform according to a control signalto output a modulated first voltage. The switch unit 102 may be formedof MOS transistors. A PWM (Pulse Width Modulation) control is performedon the MOS transistors to perform a chopping modulation on the voltagewith the steamed bun waveform.

The transformer 103 includes a primary winding, a plurality of secondarywindings and an auxiliary winding. The transformer 103 is configured tooutput a plurality of voltages with pulsating waveforms via theplurality of secondary windings according to the modulated firstvoltage, and to couple the modulated first voltage via the auxiliarywinding. The synthesizing unit 104 is configured to synthesize theplurality of voltages to output a second alternating current. For eachcycle of the second alternating current, an absolute value of a peakvoltage of a positive half is greater than that of a trough voltage of anegative half. A voltage waveform of the second alternating current isillustrated in FIG. 4.

In an embodiment of the present disclosure, as illustrated in FIG. 1,the power adapter may adopt a flyback switch unit. The transformer 103includes a primary winding, a first secondary winding, a secondsecondary winding and an auxiliary winding. An end of the primarywinding is coupled to a first output end of the first rectifier 101. Asecond output end of the first rectifier 101 is grounded. Another end ofthe primary winding is coupled to the switch unit 102 (for example, ifthe switch unit 102 is a MOS transistor, the other end of the primarywinding is coupled to a drain of the MOS transistor). The firstsecondary winding and the second secondary winding are coupled to thesynthesizing unit 104 respectively. The transformer 103 is configured tooutput a second voltage with a second pulsating waveform via the firstsecondary winding according to the modulated first voltage, and tooutput a third voltage with a third pulsating waveform via the secondsecondary winding according to the modulated first voltage. Thesynthesizing unit 104 is configured to synthesize the second voltage andthe third voltage to output the second alternating current.

In embodiments of the present disclosure, as illustrated in FIG. 2 andFIG. 3, the synthesizing unit 104 may include two controllable switchcircuits including electronic switch elements such as MOS transistors, acontrol module configured to control the two controllable switchcircuits to switch on or off. The two controllable switch circuits areswitched on and off alternately. For example, when the control modulecontrols one of the two controllable switch circuits to switch on andcontrols the other one of the two controllable switch circuits to switchoff, the synthesizing unit 104 outputs a half cycle waveform of thesecond alternating current. When the control module controls the one ofthe two controllable switch circuits to switch off and controls theother one of the two controllable switch circuits to switch on, thesynthesizing unit 104 outputs the other half cycle waveform of thesecond alternating current. Certainly, it should be understood that, inother embodiments of the present disclosure, the aforementioned controlunit 107 may be configured as this control module, as illustrated inFIG. 3.

The transformer 103 is a high-frequency transformer of which a workingfrequency ranges from 50 KHz to 2 MHz. The high-frequency transformer isconfigured to couple the modulated first voltage to the secondary sideso as to output via the secondary winding (such as the first secondarywinding and the second secondary winding). In embodiments of the presentdisclosure, with the high-frequency transformer, a characteristic of asmall size compared to the low-frequency transformer (also known as anindustrial frequency transformer, mainly used in the frequency of mainssupply such as alternating current of 50 Hz or 60 Hz) may be exploitedto realize miniaturization of the power adapter 1.

Further, in an embodiment of the present disclosure, the power adapterfurther includes a first charging interface 105.

As illustrated in FIG. 1, the first charging interface 105 is coupled tooutput ends of the synthesizing unit 104. The sampling unit 106 isconfigured to sample voltage and/or current at the auxiliary winding toobtain a voltage sampling value and/or a current sampling value. Thecontrol unit 107 is coupled to the sampling unit 106 and the switch unit102 respectively. The control unit 107 is configured to output thecontrol signal to the switch unit 102, and to adjust a duty ratio of thecontrol signal according to the current sampling value and/or thevoltage sampling value, such that the second alternating current meets acharging requirement of the terminal 2.

As illustrated in FIG. 1, the terminal 2 includes a battery 202.

In an embodiment, the terminal 2 further includes a second charginginterface 201. The second charging interface 201 is coupled to thebattery 202. When the second charging interface 201 is coupled to thefirst charging interface 105, the second charging interface 201 isconfigured to apply the second alternating current to the battery 202,so as to charge the battery 202.

It should be noted that, the second alternating current meeting thecharging requirement means that, a peak voltage/mean voltage and a peakcurrent/mean current of the second alternating current need to meet thecharging voltage and charging current correspondingly when the batteryis charged. In other words, the control unit 107 is configured to adjustthe duty ratio of the control signal (such as a PWM signal) according toa coupling and sampling of the auxiliary winding, so as to adjust theoutput of the synthesizing unit 104 in real time and realize aclosed-loop adjusting control, such that the second alternating currentmeets the charging requirement of the terminal 2, thus ensuring thestable and safe charging of the battery. In detail, a waveform of acharging voltage outputted to a battery is illustrated in FIG. 4, inwhich the waveform of the charging voltage is adjusted according to theduty ratio of the PWM signal.

It can be understood that, when adjusting the duty ratio of the PWMsignal, an adjusting instruction may be generated according to thevoltage sampling value, or according to the current sampling value, oraccording to the voltage sampling value and the current sampling value.

Therefore, in embodiments of the present disclosure, by controlling theswitch unit 102, a PWM chopping modulation is directly performed on thefirst voltage with the first pulsating waveform i.e. the steamed bunwaveform after a full-bridge rectification, and then a modulated voltageis sent to the high-frequency transformer and is coupled from theprimary side to the secondary side via the high-frequency transformer,and then the second alternating current with the alternating currentwaveform is outputted after a wave composition or a waveform splicingperformed by the synthesizing unit. The second alternating current isdirectly transmitted to the battery so as to realize fast charging tothe battery. The voltage magnitude of the second alternating current maybe adjusted according to the duty ratio of the PWM signal, such that theoutput of the power adapter may meet the charging requirement of thebattery. It can be seen from that, the power adapter according toembodiments of the present disclosure, without providing electrolyticcondensers at the primary side and the secondary side, may directlycharge the battery via the voltage with the alternating currentwaveform, such that a size of the power adapter may be reduced, thusrealizing miniaturization of the power adapter, and decreasing costgreatly.

In an embodiment of the present disclosure, the control unit 107 may bean MCU (micro controller unit), which means that the control unit 107may be a micro processor integrated with a switch driving controlfunction, a voltage and current adjusting control function.

According to an embodiment of the present disclosure, the control unit107 is further configured to adjust a frequency of the control signalaccording to the voltage sampling value and/or the current samplingvalue. That is, the control unit 107 is further configured to control tooutput the PWM signal to the switch unit 102 for a continuous timeperiod, and then to stop outputting for a predetermined time period andthen to restart to output the PWM signal. In this way, the voltageapplied to the battery is intermittent, thus realizing the intermittentcharging of the battery, which avoids a safety hazard caused by heatingphenomenon occurring when the battery is charged continuously andimproves the reliability and safety of the charging to the battery.

Under a low temperature condition, since the conductivity of ions andelectrons in a lithium battery decreases, it is prone to intensifydegree of polarization during a charging process for the lithiumbattery. A continuous charging not only makes this polarization seriousbut also increases a possibility of lithium precipitation, thusaffecting safety performance of the battery. Furthermore, the continuouscharging may accumulate heat generated due to the charging, thus leadingto an increasing of internal temperature of the battery. When thetemperature exceeds a certain value, performance of the battery may belimited, and possibility of safety hazard is increased.

In embodiments of the present disclosure, by adjusting the frequency ofthe control signal, the power adapter outputs intermittently, whichmeans that a battery resting process is introduced into the chargingprocess, such that the lithium precipitation due to the polarizationduring the continuous charging is reduced and continuous accumulation ofgenerated heat may be avoided to realize drop in the temperature, thusensuring the safety and reliability of charging to the battery.

The control signal outputted to the switch unit 102 is illustrated inFIG. 5, for example. Firstly, the PWM signal is outputted for acontinuous time period, then output of the PWM signal is stopped for acertain time period, and then the PWM signal is outputted for acontinuous time period again. In this way, the control signal output tothe switch unit 102 is intermittent, and the frequency is adjustable.

As illustrated in FIG. 1, the control unit 107 is coupled to the firstcharging interface 105. The control unit 107 is further configured toobtain status information of the terminal 2 by performing acommunication with the terminal 2 via the first charging interface 105.In this way, the control unit 107 is further configured to adjust theduty ratio of the control signal (such as the PWM signal) according tothe status information of the terminal, the voltage sampling valueand/or the current sampling value.

The status information of the terminal includes an electric quantity ofthe battery, a temperature of the battery, a voltage/current of thebattery of the terminal, interface information of the terminal andinformation on a path impedance of the terminal.

In detail, the first charging interface 105 includes a power wire and adata wire. The power wire is configured to charge the battery. The datawire is configured to communicate with the terminal. When the secondcharging interface 201 is coupled to the first charging interface 105,communication query instructions may be transmitted by the power adapter1 and the terminal 2 to each other. A communication connection can beestablished between the power adapter 1 and the terminal 2 afterreceiving a corresponding reply instruction. The control unit 107 mayobtain the status information of the terminal 2, so as to negotiatedwith the terminal 2 about a charging mode and charging parameters (suchas the charging current, the charging voltage) and to control thecharging process.

The charging mode supported by the power adapter and/or the terminal mayinclude a first charging mode and a second charging mode. A chargingspeed of the second charging mode is faster than that of the firstcharging mode. For example, a charging current of the second chargingmode is greater than that of the first charging mode. In general, thefirst charging mode may be understood as a charging mode in which arated output voltage is 5V and a rated output current is less than orequal to 2.5A. In addition, in the first charging mode, D+ and D− in thedata wire of an output port of the power adapter may be short-circuited.On the contrary, in the second charging mode according to embodiments ofthe present disclosure, the power adapter may realize data exchange bycommunicating with the terminal via D+ and D− in the data wire, i.e.,fast charging instructions may be sent by the power adapter and theterminal to each other. The power adapter sends a fast charging queryinstruction to the terminal. After receiving a fast charging replyinstruction from the terminal, the power adapter obtains the statusinformation of the terminal and starts the second charging modeaccording to the fast charging reply instruction. The charging currentin the second charging mode may be greater than 2.5A, for example, maybe 4.5A or more. The first charging mode is not limited in embodimentsof the present disclosure. As long as the power adapter supports twocharging modes one of which has a charging speed (or current) greaterthan the other charging mode, the charging mode with a slower chargingspeed may be regarded as the first charging mode. As to the chargingpower, the charging power in the second charging mode may be greaterthan or equal to 15 W.

The first charging mode is a normal charging mode and the secondcharging mode is a fast charging mode. Under the normal charging mode,the power adapter outputs a relatively small current (typically lessthan 2.5 A) or charges the battery in the mobile terminal with arelatively small power (typically less than 15 W). While, under the fastcharge mode, the power adapter outputs a relatively large current(typically greater than 2.5A, such as 4.5A, 5A or higher) or charges thebattery in the mobile terminal with a relatively large power (typicallygreater than or equal to 15 W), compared to the normal charging mode. Inthe normal charging mode, it may take several hours to fully fill alarger capacity battery (such as a battery with 3000 mAh), while in thefast charging mode, the period of time may be significantly shortenedwhen the larger capacity battery is fully filled, and the charging isfaster.

The control unit 107 communicates with the terminal 2 via the firstcharging interface 105 to determine the charging mode. The charging modeincludes the second charging mode and the first charging mode.

In detail, the power adapter is coupled to the terminal via a universalserial bus (USB) interface. The USB interface may be a general USBinterface, or a micro USB interface. A data wire in the USB interface isconfigured as the data wire in the first charging interface, andconfigured for a bidirectional communication between the power adapterand the terminal. The data wire may be D+ and/or D− wire in the USBinterface. The bidirectional communication may refer to an informationinteraction performed between the power adapter and the terminal.

The power adapter performs the bidirectional communication with theterminal via the data wire in the USB interface, so as to determine tocharge the terminal in the second charging mode.

It should be noted that, during a process that the power adapter and theterminal negotiate whether to charge the terminal in the second chargingmode, the power adapter may only keep a coupling with the terminal butdoes not charge the terminal, or charges the terminal in the firstcharging mode or charges the terminal with small current, which is notlimited herein.

The power adapter adjusts a charging current to a charging currentcorresponding to the second charging mode, and charges the terminal.After determining to charge the terminal in the second charging mode,the power adapter may directly adjust the charging current to thecharging current corresponding to the second charging mode or maynegotiate with the terminal about the charging current of the secondcharging mode. For example, the charging current corresponding to thesecond charging mode may be determined according to a current electricquantity of the battery of the terminal.

In embodiments of the present disclosure, the power adapter does notincrease the output current blindly for fast charging, but needs toperform the bidirectional communication with the terminal so as tonegotiate whether to adopt the second charging mode. In contrast to therelated art, the safety of fast charging is improved.

As an embodiment, when the control unit 107 performs the bidirectionalcommunication with the terminal via the first charging interface so asto determine to charge the terminal in the second charging mode, thecontrol unit 107 is configured to send a first instruction to theterminal and to receive a first reply instruction from the terminal. Thefirst instruction is configured to query the terminal whether to startthe second charging mode. The first reply instruction is configured toindicate that the terminal agrees to start the second charging mode.

As an embodiment, before the control unit sends the first instruction tothe terminal, the power adapter is configured to charge the terminal inthe first charging mode. The control unit is configured to send thefirst instruction to the terminal when determining that a chargingduration of the first charging mode is greater than a predeterminedthreshold.

It should be understood that, when the power adapter determines that thecharging duration of the first charging mode is greater than thepredetermined threshold, the power adapter may determine that theterminal has identified it as a power adapter, such that the fastcharging query communication may start.

As an embodiment, after determining the terminal is charged for apredetermined time period with a charging current greater than or equalto a predetermined current threshold, the power adapter is configured tosend the first instruction to the terminal.

As an embodiment, the control unit is further configured to control thepower adapter to adjust a charging current to a charging currentcorresponding to the second charging mode by controlling the switchunit. Before the power adapter charges the terminal with the chargingcurrent corresponding to the second charging mode, the control unit isconfigured to perform the bidirectional communication with the terminalvia the data wire of the first charging interface to determine acharging voltage corresponding to the second charging mode, and tocontrol the power adapter to adjust a charging voltage to the chargingvoltage corresponding to the second charging mode.

As an embodiment, when the control unit performs the bidirectionalcommunication with the terminal via the data wire of the first charginginterface to determine the charging voltage corresponding to the secondcharging mode, the control unit is configured to send a secondinstruction to the terminal, to receive a second reply instruction sentfrom the terminal, and to determine the charging voltage correspondingto the second charging mode according to the second reply instruction.The second instruction is configured to query whether a current outputvoltage of the power adapter is suitable for being used as the chargingvoltage corresponding to the second charging mode. The second replyinstruction is configured to indicate that the current output voltage ofthe power adapter is suitable, high or low.

As an embodiment, before controlling the power adapter to adjust thecharging current to the charging current corresponding to the secondcharging mode, the control unit is further configured to perform thebidirectional communication with the terminal via the data wire of thefirst charging interface to determine the charging current correspondingto the second charging mode.

As an embodiment, when performing the bidirectional communication withthe terminal via the data wire of the first charging interface todetermine the charging current corresponding to the second chargingmode, the control unit is configured to send a third instruction to theterminal, to receive a third reply instruction sent from the terminaland to determine the charging current corresponding to the secondcharging mode according to the third reply instruction. The thirdterminal is configured to query a maximum charging current supported bythe terminal. The third reply instruction is configured to indicate themaximum charging current supported by the terminal.

The power adapter may determine the above maximum charging current asthe charging current corresponding to the second charging mode, or mayset the charging current as a charging current less than the maximumcharging current.

As an embodiment, during a process that the power adapter charges theterminal in the second charging mode, the control unit is furtherconfigured to perform the bidirectional communication with the terminalvia the data wire of the first charging interface, so as to continuouslyadjust a charging current outputted to the battery from the poweradapter by controlling the switch unit.

The power adapter may query the status information of the terminalcontinuously, for example, query the voltage of the battery of theterminal, the electric quantity of the battery, etc., so as tocontinuously adjust the charging current outputted from the poweradapter.

As an embodiment, when the control unit performs the bidirectionalcommunication with the terminal via the data wire of the first charginginterface to continuously adjust the charging current outputted to thebattery from the power adapter by controlling the switch unit, thecontrol unit is configured to send a fourth instruction to the terminal,to receive a fourth reply instruction sent by the terminal, and toadjust the charging current outputted to the battery from the poweradapter by controlling the switch unit according to the current voltageof the battery. The fourth instruction is configured to query a currentvoltage of the battery in the terminal. The fourth reply instruction isconfigured to indicate the current voltage of the battery in theterminal.

As an embodiment, the control unit is configured to adjust the chargingcurrent outputted to the battery from the power adapter to a chargingcurrent value corresponding to the current voltage of the battery bycontrolling the switch unit according to the current voltage of thebattery and a predetermined correspondence between battery voltagevalues and charging current values.

In detail, the power adapter may store the correspondence betweenbattery voltage values and charging current values in advance. The poweradapter may also perform the bidirectional communication with theterminal via the data wire of the first charging interface to obtainfrom the terminal the correspondence between battery voltage values andcharging current values stored in the terminal.

As an embodiment, during the process that the power adapter charges theterminal in the second charging mode, the control unit is furtherconfigured to determine whether there is a poor contact between thefirst charging interface and the second charging interface by performingthe bidirectional communication with the terminal via the data wire ofthe first charging interface. When determining that there is the poorcontact between the first charging interface and the second charginginterface, the control unit is configured to control the power adapterto quit the second charging mode.

As an embodiment, before determining whether there is the poor contactbetween the first charging interface and the second charging interface,the control unit is further configured to receive information indicatinga path impedance of the terminal from the terminal. The control unit isconfigured to send a fourth instruction to the terminal. The fourthinstruction is configured to query a current voltage of the battery inthe terminal. The control unit is configured to receive a fourth replyinstruction sent by the terminal. The fourth reply instruction isconfigured to indicate the current voltage of the battery in theterminal. The control unit is configured to determine a path impedancefrom the power adapter to the battery according to an output voltage ofthe power adapter and the current voltage of the battery and determineswhether there is the poor contact between the first charging interfaceand the second charging interface according to the path impedance fromthe power adapter to the battery, the path impedance of the terminal,and a path impedance of a charging wire between the power adapter andthe terminal.

The terminal may record the path impedance thereof in advance. Forexample, since the terminals in a same type have a same structure, thepath impedance of the terminals in the same type is set to a same valuewhen configuring factory settings. Similarly, the power adapter mayrecord the path impedance of the charging wire in advance. When thepower adapter obtains the voltage cross two ends of the battery of theterminal, the path impedance of the whole path can be determinedaccording to the voltage drop cross two ends of the battery and currentof the path. When the path impedance of the whole path>the pathimpedance of the terminal+the path impedance of the charging wire, orthe path impedance of the whole path−(the path impedance of theterminal+the path impedance of the charging wire)>an impedancethreshold, it can be considered that there is the poor contact betweenthe first charging interface and the second charging interface.

As an embodiment, before the power adapter quits the second chargingmode, the control unit is further configured to send a fifth instructionto the terminal. The fifth instruction is configured to indicate thatthere is the poor contact between the first charging interface and thesecond charging interface.

After sending the fifth instruction, the power adapter may quit thesecond charging mode or reset.

The fast charging process according to embodiments of the presentdisclosure is described from the perspective of the power adapter, andthen the fast charging process according to embodiments of the presentdisclosure will be described from the perspective of the terminal in thefollowing.

It should be understood that, the interaction between the power adapterand the terminal, relative characteristics, functions described at theterminal side correspond to descriptions at the power adapter side, thusrepetitive description will be omitted for simplification.

According to an embodiment of the present disclosure, as illustrated inFIG. 12, the terminal 2 further includes a charging control switch 203and a controller 204. The charging control switch 203, such as a switchcircuit formed of an electronic switch element, is coupled between thesecond charging interface 201 and the battery 202, and is configured toswitch on or off a charging process of the battery under a control ofthe controller 204. In this way, the charging process of the battery canbe controlled at the terminal side, thus ensuring the safety andreliability of charging to battery.

As illustrated in FIG. 13, the terminal 2 further includes acommunication unit 205. The communication unit 205 is configured toestablish a bidirectional communication between the controller 204 andthe control unit 107 via the second charging interface 201 and the firstcharging interface 105. In other words, the terminal and the poweradapter can perform the bidirectional communication via the data wire inthe USB interface. The terminal supports the first charging mode and thesecond charging mode. The charging current of the second charging modeis greater than that of the first charging mode. The controller isconfigured to perform the bidirectional communication with the controlunit via the communication unit such that the power adapter determinesto charge the terminal in the second charging mode, and the control unitcontrols the power adapter to output according to the charging currentcorresponding to the second charging mode, for charging the battery inthe terminal.

In embodiments of the present disclosure, the power adapter does notincrease the output current blindly for the fast charging, but needs toperform the bidirectional communication with the terminal to negotiatewhether to adopt the second charging mode. In contrast to the relatedart, the safety of the fast charging process is improved.

As an embodiment, the controller is configured to receive the firstinstruction sent by the control unit via the communication unit. Thefirst instruction is configured to query the terminal whether to startthe second charging mode. The controller is configured to send a firstreply instruction to the control unit via the communication unit. Thefirst reply instruction is configured to indicate that the terminalagrees to start the second charging mode.

As an embodiment, before the controller receives the first instructionsent by the control unit via the communication unit, the battery in theterminal is charged by the power adapter in the first charging mode.When the control unit determines that a charging duration of the firstcharging mode is greater than a predetermined threshold, the controlunit sends the first instruction to the communication unit in theterminal, and the controller receives the first instruction sent by thecontrol unit via the communication unit.

As an embodiment, before the power adapter outputs according to thecharging current corresponding to the second charging mode for chargingthe battery in the terminal, the controller is configured to perform thebidirectional communication with the control unit, such that the poweradapter determines the charging voltage corresponding to the secondcharging mode.

As an embodiment, the controller is configured to receive a secondinstruction sent by the control unit, and to send a second replyinstruction to the control unit. The second instruction is configured toquery whether a current output voltage of the power adapter is suitablefor being used as the charging voltage corresponding to the secondcharging mode. The second reply instruction is configured to indicatethat the current output voltage of the power adapter is suitable, highor low.

As an embodiment, the controller is configured to perform thebidirectional communication with the control unit, such that the poweradapter determines the charging current corresponding to the secondcharging mode.

The controller is configured to receive a third instruction sent by thecontrol unit, in which the third instruction is configured to query amaximum charging current supported by the terminal. The controller isconfigured to send a third reply instruction to the control unit, inwhich the third reply instruction is configured to indicate the maximumcharging current supported by the terminal, such that the power adapterdetermines the charging current corresponding to the second chargingmode according to the maximum charging current.

As an embodiment, during a process that the power adapter charges theterminal in the second charging mode, the controller is configured toperform the bidirectional communication with the control unit, such thatthe power adapter continuously adjusts a charging current outputted tothe battery.

The controller is configured to receive a fourth instruction sent by thecontrol unit, in which the fourth instruction is configured to query acurrent voltage of the battery in the terminal. The controller isconfigured to send a fourth reply instruction to the control unit, inwhich the fourth reply instruction is configured to indicate the currentvoltage of the battery in the terminal, such that the power adaptercontinuously adjusts the charging current outputted to the batteryaccording to the current voltage of the battery.

As an embodiment, during the process that the power adapter charges theterminal in the second charging mode, the controller is configured toperform the bidirectional communication with the control unit, such thatthe power adapter determines whether there is a poor contact between thefirst charging interface and the second charging interface.

The controller receives a fourth instruction sent by the control unit.The fourth instruction is configured to query a current voltage of thebattery in the terminal. The controller sends a fourth reply instructionto the control unit, in which the fourth reply instruction is configuredto indicate the current voltage of the battery in the terminal, suchthat the control unit determines whether there is the poor contactbetween the first charging interface and the second charging interfaceaccording to an output voltage of the power adapter and the currentvoltage of the battery.

As an embodiment, the controller is configured to receive a fifthinstruction sent by the control unit. The fifth instruction isconfigured to indicate that there is the poor contact between the firstcharging interface and the second charging interface.

In order to initiate and adopt the second charging mode, the poweradapter may perform a fast charging communication procedure with theterminal, for example, by one or more handshakes, so as to realize thefast charging of battery. Referring to FIG. 6, the fast chargingcommunication procedure according to embodiments of the presentdisclosure and respective stages in the fast charging process will bedescribed in detail. It should be understood that, communication actionsor operations illustrated in FIG. 6 are merely exemplary. Otheroperations or various modifications of respective operations in FIG. 6can be implemented in embodiments of the present disclosure. Inaddition, respective stages in FIG. 6 may be executed in an orderdifferent from that illustrated in FIG. 6, and it is unnecessary toexecute all the operations illustrated in FIG. 6. It should be notedthat, a curve in FIG. 6 represents a variation trend of a peak value ora mean value of the charging current, rather than a curve of actualcharging current.

As illustrated in FIG. 6, the fast charging process may include thefollowing five stages.

Stage 1:

After being coupled to a power supply providing device, the terminal maydetect a type of the power supply providing device via the data wire D+and D−. When detecting that the power supply providing device is a poweradapter, the terminal may absorb current greater than a predeterminedcurrent threshold I2, such as 1. When the power adapter detects thatcurrent outputted by the power adapter is greater than or equal to I2within a predetermined time period (such as a continuous time periodT1), the power adapter determines that the terminal has completed therecognition of the type of the power supply providing device. The poweradapter initiates a handshake communication between the power adapterand the terminal, and sends an instruction 1 (corresponding to theabove-mentioned first instruction) to query the terminal whether tostart the second charging mode (or flash charging).

When receiving a reply instruction indicating that the terminaldisagrees to start the second charging mode from the terminal, the poweradapter detects the output current of the power adapter again. When theoutput current of the power adapter is still greater than or equal to I2within a predetermined continuous time period (such as a continuous timeperiod T1), the power adapter initiates a request again to query theterminal whether to start the second charging model. The above actionsin stage 1 are repeated, until the terminal replies that it agrees tostart the second charging mode or the output current of the poweradapter is no longer greater than or equal to I2.

After the terminal agrees to start the second charging mode, the fastcharging process is initiated, and the fast charging communicationprocedure goes into stage 2.

Stage 2:

For the voltage with the steamed bun waveform outputted by the poweradapter, there may be several levels. The power adapter sends aninstruction 2 (corresponding to the above-mentioned second instruction)to the terminal to query the terminal whether the output voltage of thepower adapter matches to the current voltage of the battery (or whetherthe output voltage of the power adapter is suitable, i.e., suitable forthe charging voltage in the second charging mode), i.e., whether theoutput voltage of the power adapter meets the charging requirement.

The terminal replies that the output voltage of the power adapter ishigher, lower or suitable. When the power adapter receives a feedbackindicating that the output voltage of the power adapter is lower orhigher from the terminal, the control unit adjusts the output voltage ofthe power adapter by one level by adjusting the duty ratio of the PWMsignal, and sends the instruction 2 to the terminal again to query theterminal whether the output voltage of the power adapter matches.

The above actions in stage 2 are repeated, until the terminal replies tothe power adapter that the output voltage of the power adapter is at amatching level. And then the fast charging communication procedure goesinto stage 3.

Stage 3:

After the power adapter receives the feedback indicating that the outputvoltage of the power adapter matches from the terminal, the poweradapter sends an instruction 3 (corresponding to the above-mentionedthird instruction) to the terminal to query the maximum charging currentsupported by the terminal. The terminal returns to the power adapter themaximum charging current supported by itself, and then the fast chargingcommunication procedure goes into stage 4.

Stage 4:

After receiving a feedback indicating the maximum charging currentsupported by the terminal from the terminal, the power adapter may setan output current reference value. The control unit 107 adjusts the dutyratio of the PWM signal according to the output current reference value,such that the output current of the power adapter meets the chargingcurrent requirement of the terminal, and the fast charging communicationprocedure goes into constant current stage. The constant current stagemeans that the peak value or mean value of the output current of thepower adapter basically remains unchanged (which means that thevariation amplitude of the peak value or mean value of the outputcurrent is very small, for example within a range of 5% of the peakvalue or mean value of the output current), namely, the peak current ofthe second alternating current keeps constant in each period.

Stage 5:

When the fast charging communication procedure goes into the constantcurrent stage, the power adapter sends an instruction 4 (correspondingto the above-mentioned fourth instruction) at intervals to query thecurrent voltage of battery in the terminal. The terminal may feedback tothe power adapter the current voltage of the battery, and the poweradapter may determine according to the feedback of the current voltageof the battery whether there is a poor USB contact (i.e., a poor contactbetween the first charging interface and the second charging interface)and whether it is necessary to decrease the charging current value ofthe terminal. When the power adapter determines that there is the poorUSB contact, the power adapter sends an instruction 5 (corresponding tothe above-mentioned fifth instruction), and then the power adapter isreset, such that the fast charging communication procedure goes intostage 1 again.

In some embodiments of the present disclosure, in stage 1, when theterminal replies to the instruction 1, data corresponding to theinstruction 1 may carry data (or information) on the path impedance ofthe terminal. The data on the path impedance of the terminal may be usedin stage 5 to determine whether there is the poor USB contact.

In some embodiments of the present disclosure, in stage 2, the timeperiod from when the terminal agrees to start the second charging modeto when the power adapter adjusts the voltage to a suitable value may belimited in a certain range. If the time period exceeds a predeterminedrange, the terminal may determine that there is an exception request,thus a quick reset is performed.

In some embodiments of the present disclosure, in stage 2, the terminalmay give a feedback indicating that the output voltage of the poweradapter is suitable/matches to the power adapter when the output voltageof the power adapter is adjusted to a value higher than the currentvoltage of the battery by ΔV (ΔV is about 200-500 mV). When the terminalgives a feedback indicating that the output voltage of the power adapteris not suitable (higher or lower) to the power adapter, the control unit107 adjusts the duty ratio of the PWM signal according to the voltagesampling value, so as to adjust the output voltage of the power adapter.

In some embodiments of the present disclosure, in stage 4, the adjustingspeed of the output current value of the power adapter may be controlledto be in a certain range, thus avoiding an abnormal interruption of thefast charging due to the too fast adjusting speed.

In some embodiments of the present disclosure, in stage 5, the variationamplitude of the output current value of the power adapter may becontrolled to be within 5%, i.e., stage 5 may be regarded as theconstant current stage.

In some embodiments of the present disclosure, in stage 5, the poweradapter monitors the impedance of a charging loop in real time, i.e.,the power adapter monitors the impedance of the whole charging loop bymeasuring the output voltage of the power adapter, the charging currentand the read-out voltage of the battery in the terminal. When theimpedance of the charging loop>the path impedance of the terminal+theimpedance of the fast charging data wire, it may be considered thatthere is the poor USB contact, and thus a fast charging reset isperformed.

In some embodiments of the present disclosure, after the second chargingmode is started, a time interval of communications between the poweradapter and the terminal may be controlled to be in a certain range,such that the fast charging reset can be avoided.

In some embodiments of the present disclosure, the termination of thesecond charging mode (or the fast charging process) may be a recoverabletermination or an unrecoverable termination.

For example, when the terminal detects that the battery is fully chargedor there is the poor USB contact, the fast charging is stopped andreset, and the fast charging communication procedure goes into stage 1.When the terminal disagrees to start the second charging mode, the fastcharging communication procedure would not go into stage 2, thus thetermination of the fast charging process may be considered as anunrecoverable termination.

For another example, when an exception occurs in the communicationbetween the terminal and the power adapter, the fast charging is stoppedand reset, and the fast charging communication procedure goes intostage 1. After requirements for stage 1 are met, the terminal agrees tostart the second charging mode to recover the fast charging process,thus the termination of the fast charging process may be considered as arecoverable termination.

For another example, when the terminal detects an exception occurring inthe battery, the fast charging is stopped and reset, and the fastcharging communication procedure goes into stage 1. After the fastcharging communication procedure goes into stage 1, the terminaldisagrees to start the second charging mode. Till the battery returns tonormal and the requirements for stage 1 are met, the terminal agrees tostart the fast charging to recover the fast charging process. Thus, thetermination of fast charging process may be considered as a recoverabletermination.

It should be noted that, communication actions or operations illustratedin FIG. 6 are merely exemplary. For example, in stage 1, after theterminal is coupled to the power adapter, the handshake communicationbetween the terminal and the power adapter may be initiated by theterminal. In other words, the terminal sends an instruction 1 to querythe power adapter whether to start the second charging mode (or flashcharging). When receiving a reply instruction indicating that the poweradapter agrees to start the second charging mode from the power adapter,the terminal starts the fast charging process.

It should be noted that, communication actions or operations illustratedin FIG. 46 are merely exemplary. For example, after stage 5, there is aconstant voltage charging stage. In other words, in stage 5, theterminal may feedback the current voltage of the battery in the terminalto the power adapter. As the voltage of the battery increasescontinuously, the charging goes into the constant voltage charging stagewhen the current voltage of the battery reaches a constant voltagecharging voltage threshold. The control unit 107 adjusts the duty ratioof the PWM signal according to the voltage reference value (i.e., theconstant voltage charging voltage threshold), such that the outputvoltage of the power adapter meets the charging voltage requirement ofthe terminal, i.e., the output voltage of the power adapter basicallychanges at a constant rate. During the constant voltage charging stage,the charging current decreases gradually. When the current reduces to acertain threshold, the charging is stopped and it is illustrated thatthe battery is fully charged. The constant voltage charging refers tothat the peak voltage with the second alternating current basicallykeeps constant.

It should be noted that, in embodiments of the present disclosure,acquiring output voltage of the power adapter means that the peakvoltage or mean voltage of the second alternating current is acquired.Acquiring output current of the power adapter means that the peakcurrent or mean current of the second alternating current is acquired.

In an embodiment of the present disclosure, as illustrated in FIG. 7,the power adapter 1 further includes a rectifying and filtering unit 109and a controllable switch 108 configured to control an operation of therectifying and filtering unit 109. The rectifying and filtering unit 109is configured to perform a rectifying and filtering on one of theplurality of voltages to output a second direct current, such as 5V. Thecontrol unit 107 is further configured to control the rectifying andfiltering unit 109 to work and control the synthesizing unit 104 to stopworking by controlling the controllable switch 108 when determining thecharging mode as the first charging mode, such that the rectifying andfiltering unit 109 outputs the second direct current for charging thebattery. The control unit 107 is configured to control the rectifyingand filtering unit 109 to stop working and control the synthesizing unit104 to work by controlling the controllable switch 108 when determiningthe charging mode as the second charging mode, such that the secondalternating current is applied to the battery.

The rectifying and filtering unit 109 includes a rectifier diode and afiltering capacitor. The filtering capacitor supports a standardcharging of 5V corresponding to the first charging mode. Thecontrollable switch 108 may be formed of a semiconductor switch elementsuch as a MOS transistor. When the power adapter charges the battery inthe terminal in the first charging mode (or called as standardcharging), the control unit 107 controls the controllable switch 108 toswitch on so as to control the rectifying and filtering unit 109 to worksuch that a filtering can be performed on the output of the synthesizingunit 104. In this way, the direct charging technology is compatible,i.e., the second direct current is applied to the battery in theterminal so as to realize direct current charging of the battery. Forexample, in general, the filtering part includes an electrolyticcondenser and a common capacitor such as a small capacitor supportingstandard charging of 5V (for example, a solid-state capacitor) inparallel. Since the electrolytic condenser occupies a bigger volume, inorder to reduce the size of the power adapter, the electrolyticcondenser may be removed from the power adapter and only one capacitorwith low capacitance is left. When the first charging mode is adopted, abranch where the small capacitor is located is switched on, and thecurrent is filtered to realize a stable output with low power forperforming a direct current charging on the battery. When the secondcharging mode is adopted, the second direct current is directlyoutputted, so as to realize a fast charging of the battery.

According to an embodiment of the present disclosure, the control unit107 is further configured to obtain the charging current and/or thecharging voltage corresponding to the second charging mode according tothe status information of the terminal and to adjust the duty ratio ofthe control signal such as the PWM signal according to the chargingcurrent and/or the charging voltage corresponding to the second chargingmode, when determining the charging mode as the second charging mode. Inother words, when determining the current charging mode as the secondcharging mode, the control unit 107 obtains the charging current and/orthe charging voltage corresponding to the second charging mode accordingto the obtained status information of the terminal such as the voltage,the electric quantity and the temperature of the battery, runningparameters of the terminal and power consumption information ofapplications running on the terminal, and adjusts the duty ratio of thecontrol signal according to the charging current and/or the chargingvoltage, such that the output of the power adapter meets the chargingrequirement, thus realizing the fast charging of the battery.

The status information of the terminal includes the temperature of theterminal. When the temperature of the battery is greater than a firstpredetermined temperature threshold, or the temperature of the batteryis less than a second predetermined temperature threshold, if thecurrent charging mode is the second charging mode, the second chargingmode is switched to the first charging mode. The first predeterminedtemperature threshold is greater than the second predeterminedtemperature threshold. In other words, when the temperature of thebattery is too low (for example, corresponding to less than the secondpredetermined temperature threshold) or too high (for example,corresponding to greater than the first predetermined temperaturethreshold), it is unsuitable to perform the fast charging, such that itneeds to switch from the second charging mode to the first chargingmode. In embodiments of the present disclosure, the first predeterminedtemperature threshold and the second predetermined temperature thresholdcan be set according to actual situations, or can be written into thestorage of the control unit (such as the MCU of the power adapter).

In an embodiment of the present disclosure, the control unit 107 isfurther configured to control the switch unit 102 to switch off when thetemperature of the battery is greater than a predetermined hightemperature protection threshold. Namely, when the temperature of thebattery exceeds the high temperature protection threshold, the controlunit 107 needs to apply a high temperature protection strategy tocontrol the switch unit 102 to switch off, such that the power adapterstops charging the battery, thus realizing the high protection of thebattery and improving the safety of charging. The high temperatureprotection threshold may be different from or the same to the firsttemperature threshold. In an embodiment, the high temperature protectionthreshold is greater than the first temperature threshold.

In another embodiment of the present disclosure, the controller isfurther configured to obtain the temperature of the battery, and tocontrol the charging control switch to switch off (i.e., the chargingcontrol switch can be switched off at the terminal side) when thetemperature of the battery is greater than the predetermined hightemperature protection threshold, so as to stop the charging process ofthe battery and to ensure the safety of charging.

Moreover, in an embodiment of the present disclosure, the control unitis further configured to obtain a temperature of the first charginginterface, and to control the switch unit to switch off when thetemperature of the first charging interface is greater than apredetermined protection temperature. In other words, when thetemperature of the charging interface exceeds a certain temperature, thecontrol unit 107 needs to apply the high temperature protection strategyto control the switch unit 102 to switch off, such that the poweradapter stops charging the battery, thus realizing the high protectionof the battery and improving the safety of charging.

Certainly, in another embodiment of the present disclosure, thecontroller obtains the temperature of the first charging interface byperforming the bidirectional communication with the control unit. Whenthe temperature of the first charging interface is greater than thepredetermined protection temperature, the controller controls thecharging control switch to switch off, i.e., switches off the chargingcontrol switch at the terminal side, so as to stop the charging processof the battery, thus ensuring the safety of charging.

In detail, in an embodiment of the present disclosure, as illustrated inFIG. 8, the power adapter 1 further includes a driving unit 110 such asa MOSFET driver. The driving unit 110 is coupled between the switch unit102 and the control unit 107. The driving unit 110 is configured todrive the switch unit 102 to switch on or off according to the controlsignal. Certainly, it should be noted, in other embodiments of thepresent disclosure, the driving unit 110 may also be integrated in thecontrol unit 107.

Further, as illustrated in FIG. 8, the power adapter 1 further includesan isolation unit 111. The isolation unit 111 is coupled between thedriving unit 110 and the control unit 107, to prevent high voltages fromaffecting the control unit 107 at the secondary side of the transformer103. The isolation unit 111 may be implemented in an optical isolationmanner, or in other isolation manners. By setting the isolation unit111, the control unit 107 may be disposed at the secondary side of thepower adapter 1 (or the secondary winding side of the transformer 103),such that it is convenient to communicate with the terminal 2, and thespace design of the power adapter 1 becomes easier and simpler.

Certainly, it should be understood that, in other embodiments of thepresent disclosure, both the control unit 107 and the driving unit 110can be disposed as the primary side, in this way, an isolation unit 111can be disposed between the control unit 107 and the first charginginterface 105.

Further, it should be noted that, in embodiments of the presentdisclosure, when the control unit 107 is disposed at the secondary side,an isolation unit 111 is required, and the isolation unit 111 may beintegrated in the control unit 107. In other words, when the signal istransmitted from the primary side to the secondary side or from thesecondary side to the primary side, an isolation unit is required toprevent high voltages from affecting the control unit 107 at thesecondary side of the transformer 103.

In an embodiment of the present disclosure, as illustrated in FIG. 9,the power adapter 1 further includes a power supply unit 112. Theauxiliary winding is configured to output a fourth voltage with a fourthpulsating waveform. The power supply unit 112 is coupled to theauxiliary winding. The power supply unit 112 (for example, including afiltering voltage regulator module, a voltage converting module and thelike) is configured to convert the fourth voltage with the fourthpulsating waveform and output a first direct current, and to supplypower to the driving unit 110 and/or the control unit 107 respectively.The power supply unit 112 may be formed of a small filtering capacitor,a voltage regulator chip or other elements, performs a process andconversation on the fourth voltage with the fourth pulsating waveformand outputs the low voltage direct current such as 3.3V, 5V or the like.

In other words, the power supply of the driving unit 110 can be obtainedby performing a voltage conversation on the fourth voltage with thefourth pulsating waveform by the power supply unit 112. When the controlunit 107 is disposed at the primary side, the power supply of thecontrol unit 107 can also be obtained by performing a voltageconversation on the fourth voltage with the fourth pulsating waveform bythe power supply unit 112. As illustrated in FIG. 9, when the controlunit 107 is disposed at the primary side, the power supply unit 112provides two lines of direct current outputs, so as to supply power tothe driving unit 110 and the control unit 107 respectively. An opticalisolation unit 111 is arranged between the control unit 107 and thefirst charging interface to prevent high voltages from affecting thecontrol unit 107 at the secondary side of the transformer 103.

When the control unit 107 is disposed at the primary side and integratedwith the driving unit 110, the power supply unit 112 supplies power tothe control unit 107 only. When the control unit 107 is disposed at thesecondary side and the driving unit 110 is disposed at the primary side,the power supply unit 112 supplies power to the driving unit 110 only.The power supply to the control unit 107 is realized by the secondaryside, for example, a power supply unit converts the second alternatingcurrent outputted by the synthesizing unit 104 to a first direct currentto supply power to the control unit 107.

Moreover, in embodiments of the present disclosure, several smallcapacitors are coupled in parallel to the output end of first rectifier101 for filtering. Or the output end of the first rectifier 101 iscoupled to an LC filtering circuit.

In embodiments of the present disclosure, the sampling unit isconfigured to sample voltage and/or current of the fourth voltage toobtain the voltage sampling value and/or the current sampling value.

In detail, in an embodiment of the present disclosure, as illustrated inFIG. 10, the sampling unit 106 includes a first current sampling circuit1061 and a first voltage sampling circuit 1062. The first currentsampling circuit 1061 is configured to sample the current at theauxiliary winding so as to obtain the current sampling value. The firstvoltage sampling circuit 1062 is configured to sample the voltage at theauxiliary winding so as to obtain the voltage sampling value.

In an embodiment of the present disclosure, the first current samplingcircuit 1061 can sample the current at the auxiliary winding by samplingvoltage on a resistor (current detection resistor) between a first endof the auxiliary winding and the ground. The first voltage samplingcircuit 1062 can sample the voltage at the auxiliary winding by samplingthe voltage cross two ends of the auxiliary winding.

Moreover, in an embodiment of the present disclosure, as illustrated inFIG. 10, the first voltage sampling circuit 1062 includes a peak voltagesampling and holding unit, a cross-zero sampling unit, a bleeder unitand an AD sampling unit. The peak voltage sampling and holding unit isconfigured to sample and hold a peak voltage of the fourth voltage. Thecross-zero sampling unit is configured to sample a zero crossing pointof the fourth voltage. The bleeder unit is configured to drain off thepeak voltage sampling and holding unit at the zero crossing point. TheAD sampling unit is configured to sample the peak voltage in the peakvoltage sampling and holding unit so as to obtain the voltage samplingvalue.

By providing with the peak voltage sampling and holding unit, thecross-zero sampling unit, the bleeder unit and the AD sampling unit inthe first voltage sampling circuit 1062, the voltage at the auxiliarywinding may be sampled accurately, and it can be guaranteed that thevoltage sampling value keeps consistent with the first voltage, i.e.,the phase and variation trend of magnitude of the voltage sampling valueare consistent with those of the first voltage respectively.

According to an embodiment of the present disclosure, as illustrated inFIG. 11, the power adapter 1 further includes a second voltage samplingcircuit 114. The second voltage sampling circuit 114 is configured tosample the first voltage with the first pulsating waveform. The secondvoltage sampling circuit 114 is coupled to the control unit 107. Whenthe voltage value sampled by the second voltage sampling circuit 114 isgreater than a first predetermined voltage value, the control unit 107controls the switch unit 102 to switch on for a predetermined timeperiod, for performing a discharge on the surge voltage, spike voltagein the first voltage with the first pulsating waveform.

As illustrated in FIG. 11, the second voltage sampling circuit 114 canbe coupled to the first output end and the second output end of thefirst rectifier 101, so as to sample the first voltage with the firstpulsating waveform. The control unit 107 performs a determination on thevoltage value sampled by the second voltage sampling circuit 114. Whenthe voltage value sampled by the second voltage sampling circuit 114 isgreater than the first predetermined voltage value, it indicates thatthe power adapter 1 is disturbed by lightning stroke and the surgevoltage is generated. At this time, a leakage is required for the surgevoltage to ensure the safety and reliability of charging. The controlunit 107 controls the switch unit 102 to switch on for a certain timeperiod, to form a leakage circuit, such that the leakage is performed onthe surge voltage caused by lightning stroke, thus avoiding thedisturbance caused by the lightning stroke when the power adaptercharges the terminal, and effectively improving the safety andreliability of the charging of the terminal. The first predeterminedvoltage value may be determined according to actual situations.

In an embodiment of the present disclosure, during a process that thepower adapter charges the battery in the terminal, the control unit 107is further configured to control the switch unit 102 to switch off whenthe voltage sampling value is greater than a second predeterminedvoltage value. Namely, the control unit 107 further performs adetermination on the voltage sampling value. When the voltage samplingvalue is greater than the second predetermined voltage value, itindicates that the voltage outputted by the power adapter 1 is too high.At this time, the control unit 107 controls the power adapter to stopcharging the terminal by controlling the switch unit 102 to switch off.In other words, the control unit 107 realizes the over-voltageprotection of the power adapter by controlling the switch unit 102 toswitch off, thus ensuring the safety of charging.

Certainly, in an embodiment of the present disclosure, the controllerobtains the voltage sampling value by performing a bidirectionalcommunication with the control unit, and controls the charging controlswitch to switch off when the voltage sampling value is greater than thesecond predetermined voltage value. Namely, the charging control switchis controlled to switch off at the terminal side, so as to stop thecharging process, such that the safety of charging can be ensured.

Further, the control unit 107 is further configured to control theswitch unit 102 to switch off when the current sampling value is greaterthan a predetermined current value. In other words, the control unit 107further performs a determination on the current sampling value. When thecurrent sampling value is greater than the predetermined current value,it indicates that the current outputted by the power adapter 1 is toohigh. At this time, the control unit 107 controls the power adapter tostop charging the terminal by controlling the switch unit 102 to switchoff. In other words, the control unit 107 realizes the over-currentprotection of the power adapter by controlling the switch unit 102 toswitch off, thus ensuring the safety of charging.

Similarly, the controller obtains the current sampling value byperforming the bidirectional communication with the control unit, andcontrols to switch off the charging control switch when the currentsampling value is greater than the predetermined current value. In otherwords, the charging control switch is controlled to be switched off atthe terminal side, so as to stop the charging process of the battery,thus ensuring the safety of charging.

The second predetermined voltage value and the predetermined currentvalue may be set or written into a storage of the control unit (forexample, the MCU of the power adapter) according to actual situations.

In embodiments of the present disclosure, the terminal may be a mobileterminal, such as a mobile phone, a mobile power supply such as a powerbank, a multimedia player, a notebook PC, a wearable device or the like.

With the charging system according to embodiments of the presentdisclosure, the power adapter is controlled to output the secondalternating current, and the second alternating current outputted by thepower adapter is directly applied to the battery of the terminal, thusrealizing fast charging to the battery directly by the outputvoltage/current with alternating current waveform, and realizing aclosed-loop control on the output of the power adapter by sampling theauxiliary winding to ensure that the second alternating current meetsthe charging requirement. In contrast to the conventional constantvoltage and constant current, a magnitude of the output voltage/currentwith alternating current waveform changes periodically and an absolutevalue of a peak voltage of a positive half of each cycle is greater thanthat of a trough voltage of a negative half of the cycle, such that alithium precipitation of the lithium battery may be reduced, the servicelife of the battery may be improved, and a probability and intensity ofarc discharge of a contact of a charging interface may be reduced, theservice life of the charging interface may be prolonged, and it isbeneficial to reduce polarization effect of the battery, improvecharging speed, and decrease heat emitted by the battery, thus ensuringa reliability and safety of the terminal during the charging. Moreover,since the power adapter outputs the voltage with the alternating currentwaveform, it is unnecessary to provide an electrolytic condenser in thepower adapter, which not only realizes simplification andminiaturization of the power adapter, but also decreases cost greatly.

Embodiments of the present disclosure further provide a power adapter.The power adapter includes a first rectifier, a switch unit, atransformer, a synthesizing unit, a first charging interface, a samplingunit, and a control unit. The first rectifier is configured to rectifyan input first alternating current and output a first voltage with afirst pulsating waveform. The switch unit is configured to modulate thefirst voltage according to a control signal and output a modulated firstvoltage. The transformer has a primary winding, a plurality of secondarywindings, and an auxiliary winding, and is configured to output aplurality of voltages with pulsating waveforms via the plurality ofsecondary windings according to the modulated first voltage, and tocouple the modulated first voltage via the auxiliary winding. Thesynthesizing unit is configured to synthesize the plurality of voltagesto output a second alternating current, in which, for each cycle of thesecond alternating current, an absolute value of a peak voltage of apositive half is greater than that of a trough voltage of a negativehalf. The first charging interface is coupled to an output end of thesynthesizing unit, and configured to apply the second alternatingcurrent to a battery in a terminal via a second charging interface ofthe terminal when the first charging interface is coupled to the secondcharging interface, in which the second charging interface is coupled tothe battery. The sampling unit is configured to sample voltage and/orcurrent at the auxiliary winding to obtain a voltage sampling valueand/or a current sampling value. The control unit is coupled to thesampling unit and the switch unit respectively, and configured to outputthe control signal to the switch unit, and to adjust a duty ratio of thecontrol signal according to the current sampling value and/or thevoltage sampling value, such that the second alternating current meets acharging requirement of the terminal.

With the power adapter according to embodiments of the presentdisclosure, the second alternating current is outputted via the firstcharging interface, and the second alternating current is directlyapplied to the battery of the terminal via the second charging interfaceof the terminal, thus realizing fast charging to the battery directly bythe output voltage/current with the alternating current waveform, andrealizing a closed-loop control on the output of the power adapter bysampling the auxiliary winding to ensure that the second alternatingcurrent meets the charging requirement. In contrast to the conventionalconstant voltage and constant current, a magnitude of the outputvoltage/current with the alternating current waveform changesperiodically and an absolute value of a peak voltage of a positive halfof each cycle of the second alternating current is greater than that ofa trough voltage of a negative half of the cycle, such that a lithiumprecipitation of the lithium battery may be reduced, the service life ofthe battery may be improved, and a probability and intensity of arcdischarge of a contact of a charging interface may be reduced, theservice life of the charging interface may be prolonged, and it isbeneficial to reduce polarization effect of the battery, improvecharging speed, and decrease heat emitted by the battery, thus ensuringa reliability and safety of the terminal during the charging. Moreover,since the voltage with the alternating current waveform is output, it isunnecessary to provide an electrolytic condenser, which not onlyrealizes simplification and miniaturization of the power adapter, butalso decreases cost greatly.

FIG. 14 is a flow chart of a charging method according to embodiments ofthe present disclosure. As illustrated in FIG. 14, the charging methodincludes the following.

At block S1, a first rectification is performed on alternating currentinputted into the power adapter to output a first voltage with a firstpulsating waveform.

In other words, a first rectifier in the power adapter rectifies theinputted alternating current (i.e., the mains supply, such asalternating current of 220V, 50 Hz or 60 Hz) and outputs the firstvoltage (for example, 100 Hz or 120 Hz) with the first pulsatingwaveform, such as a voltage with a steamed bun waveform.

In an embodiment of the present disclosure, the power adapter furtherincludes a first charging interface and the terminal further includes asecond charging interface. When the first charging interface is coupledto the second charging interface, block S1 is performed.

At block S2, the first voltage with the first pulsating waveform ismodulated by a switch unit, and then is converted by a transformer toobtain a plurality of voltages with pulsating waveforms.

The switch unit may be formed of a MOS transistor. A PWM control isperformed on the MOS transistor to perform a chopping modulation on thevoltage with the steamed bun waveform. And then, the modulated firstvoltage is coupled to a secondary side by the transformer, such that thesecondary winding outputs the plurality of voltages.

In an embodiment of the present disclosure, a high-frequency transformeris used for conversion, such that the size of the transformer is small,thus realizing miniaturization of the power adapter with high-power.

At block S3, the plurality of voltages are synthesized to output asecond alternating current. For each period of the second alternatingcurrent, an absolute value of a peak voltage of a positive half isgreater than that of a trough voltage of a negative half. A voltagewaveform of the second alternating current is illustrated in FIG. 4.

In an embodiment of the present disclosure, the second alternatingcurrent is applied to the battery of the terminal via the secondcharging interface.

In an embodiment of the present disclosure, the transformer includes aprimary winding, a first secondary winding, a second secondary winding.The transformer is configured to output a second voltage with a secondpulsating waveform via the first secondary winding according to themodulated first voltage, and to output a third voltage with a thirdpulsating waveform via the second secondary winding according to themodulated first voltage. And then, the second voltage and the thirdvoltage are synthesized by the synthesizing unit to output the secondalternating current. The second alternating current is applied to thebattery of the terminal via the second charging interface, so as tocharge the battery of the terminal.

At block S4, primary output of the transformer is coupled via theauxiliary winding of the transformer and voltage and/or current at theauxiliary winding is sampled to obtain a voltage sampling value and/or acurrent sampling value.

At block S5, a duty ratio of a control signal for controlling the switchunit is adjusted according to the voltage sampling value and/or thecurrent sampling value, such that the second alternating current meets acharging requirement.

It should be noted that, the second alternating current meeting thecharging requirement means that, at least a peak voltage/mean voltageand a peak current/mean current of the second alternating current needto meet the charging voltage and charging current when the battery ischarged. In other words, the duty ratio of the control signal (such as aPWM signal) is adjusted according to a coupling and sampling of theauxiliary winding, so as to adjust the output of the power adapter inreal time and realize a closed-loop adjusting control, such that thesecond alternating current meets the charging requirement of theterminal, thus ensuring the stable and safe charging of the battery. Indetail, a waveform of a charging voltage outputted to a battery isillustrated in FIG. 4, in which the waveform of the charging voltage isadjusted according to the duty ratio of the PWM signal.

In an embodiment of the present disclosure, by controlling the switchunit, a chopping modulation is directly performed on the first voltagewith the first pulsating waveform i.e., the steamed bun waveform after afull-bridge rectification, and then a modulated voltage is sent to thehigh-frequency transformer and is coupled from the primary side to thesecondary side via the high-frequency transformer, and then the secondalternating current is outputted after a wave composition or a waveformsplicing performed by the synthesizing unit. The second alternatingcurrent is directly transmitted to the battery so as to realize fastcharging to the battery. The magnitude of the second alternating currentmay be adjusted according to the duty ratio of the PWM signal, such thatthe output of the power adapter may meet the charging requirement of thebattery. It can be seen from that, electrolytic condensers at theprimary side and the secondary side in the power adapter can be removed,and the battery can be directly charged via the second alternatingcurrent, such that a size of the power adapter may be reduced, thusrealizing miniaturization of the power adapter, and decreasing costgreatly.

According to an embodiment of the present disclosure, a frequency of thecontrol signal is adjusted according to the voltage sampling valueand/or the current sampling value. That is, the output of the PWM signalto the switch unit is controlled to maintain for a continuous timeperiod, and then stop for a predetermined time period and then restart.In this way, the voltage applied to the battery is intermittent, thusrealizing the intermittent charging of the battery, which avoids asafety hazard caused by heating phenomenon occurring when the battery ischarged continuously and improves the reliability and safety of thecharging to the battery. The control signal outputted to the switch unitis illustrated in FIG. 5.

Further, the above charging method includes: performing a communicationwith the terminal via the first charging interface to obtain statusinformation of the terminal, and adjusting the duty ratio of the controlsignal according to the status information of the terminal, the voltagesampling value and/or current sampling value.

In other words, when the second charging interface is coupled to thefirst charging interface, the power adapter and the terminal may sendcommunication query instructions to each other, and a communicationconnection can be established between the power adapter and the terminalafter corresponding reply instructions are received, such that the poweradapter can obtain the status information of the terminal, negotiateswith the terminal about the charging mode and the charging parameter(such as the charging current, the charging voltage) and controls thecharging process.

According to an embodiment of the present disclosure, a fourth voltagewith a fourth pulsating waveform can be outputted via the auxiliarywinding, and the fourth voltage with the fourth pulsating waveform canbe sampled to obtain the voltage sampling value and/or the currentsampling value.

In detail, the transformer can be provided with the auxiliary winding.The auxiliary winding can generate the fourth voltage with the fourthpulsating waveform according to the modulated first voltage. The outputvoltage of the power adapter can be reflected by detecting the fourthvoltage with the fourth pulsating waveform, and the duty ratio of thecontrol signal can be adjusted according to the voltage sampling value,such that the output of the power adapter meets the charging requirementof the battery.

In an embodiment of the present disclosure, sampling the fourth voltageto obtain the voltage sampling value including: sampling and holding apeak voltage of the fourth voltage, and sampling a zero crossing pointof the voltage at the primary winding; performing a leakage on a peakvoltage sampling and holding unit configured for sampling and holdingthe peak voltage at the zero crossing point; and sampling the peakvoltage in the peak voltage sampling and holding unit so as to obtainthe voltage sampling value. In this way, an accurate sampling can beperformed on the peak voltage outputted by the power adapter, and it canbe guaranteed that the voltage sampling value keeps synchronous with thepeak voltage of the first voltage, i.e., the phase and variation trendof magnitude of the voltage sampling value are consistent with those ofthe peak voltage of the first voltage respectively.

Further, in an embodiment of the present disclosure, the above chargingmethod includes: sampling the first voltage with the first pulsatingwaveform, and controlling the switch unit to switch on for apredetermined time period for performing a discharge on the peak voltagesuch as surge voltage, spike voltage in the first voltage with the firstpulsating waveform when a sampled voltage value is greater than a firstpredetermined voltage value.

The first voltage with the first pulsating waveform is sampled so as todetermine the sampled voltage value. When the sampled voltage value isgreater than the first predetermined voltage value, it indicates thatthe power adapter is disturbed by lightning stroke and the surge voltageis generated. At this time, a leakage is required for the surge voltageto ensure the safety and reliability of charging. It is required tocontrol the switch unit to switch on for a certain time period, to forma leakage circuit, such that the leakage is performed on the surgevoltage caused by lightning stroke, thus avoiding the disturbance causedby the lightning stroke when the power adapter charges the terminal, andeffectively improving the safety and reliability of the charging of theterminal. The first predetermined voltage value may be determinedaccording to actual situations.

According an embodiment of the present disclosure, a communication withthe terminal is performed via the first charging interface to determinethe charging mode. When the charging mode is determined as the secondcharging mode, the charging current and/or charging voltagecorresponding to the second charging mode can be obtained according tothe status information of the terminal, so as to adjust the duty ratioof the control signal according to the charging current and/or chargingvoltage corresponding to the second charging mode. The charging modeincludes the second charging mode and the first charging mode.

In other words, when the current charging mode is determined as thesecond charging mode, the charging current and/or charging voltagecorresponding to the second charging mode can be obtained according tothe status information of the terminal, such as the voltage, electricquantity, temperature of the battery, running parameters of the terminaland power consumption information of applications running on theterminal or the like. And the duty ratio of the control signal isadjusted according to the obtained charging current and/or chargingvoltage, such that the output of the power adapter meets the chargingrequirement, thus realizing the fast charging of the terminal.

The status information of the terminal includes the temperature of thebattery. When the temperature of the battery is greater than a firstpredetermined temperature threshold, or the temperature of the batteryis less than a second predetermined temperature threshold, if thecurrent charging mode is the second charging mode, the second chargingmode is switched to the first charging mode. The first predeterminedtemperature threshold is greater than the second predeterminedtemperature threshold. In other words, when the temperature of thebattery is too low (for example, corresponding to less than the secondpredetermined temperature threshold) or too high (for example,corresponding to greater than the first predetermined temperaturethreshold), it is unsuitable to perform the fast charging, such that itneeds to switch from the second charging mode to the first chargingmode. In embodiments of the present disclosure, the first predeterminedtemperature threshold and the second predetermined temperature thresholdcan be set according to actual situations.

In an embodiment of the present disclosure, the switch unit iscontrolled to switch off when the temperature of the battery is greaterthan a predetermined high temperature protection threshold. Namely, whenthe temperature of the battery exceeds the high temperature protectionthreshold, it needs to apply a high temperature protection strategy tocontrol the switch unit to switch off, such that the power adapter stopscharging the battery, thus realizing the high protection of the batteryand improving the safety of charging. The high temperature protectionthreshold may be different from or the same to the first temperaturethreshold. In an embodiment, the high temperature protection thresholdis greater than the first temperature threshold.

In another embodiment of the present disclosure, the terminal furtherobtains the temperature of the battery, and controls to stop chargingthe battery (for example by controlling a charging control switch toswitch off at the terminal side) when the temperature of the battery isgreater than the predetermined high temperature protection threshold, soas to stop the charging process of the battery and to ensure the safetyof charging.

Moreover, in an embodiment of the present disclosure, the chargingmethod further includes: obtaining a temperature of the first charginginterface, and controlling the switch unit to switch off when thetemperature of the first charging interface is greater than apredetermined protection temperature. In other words, when thetemperature of the charging interface exceeds a certain temperature, thecontrol unit needs to apply the high temperature protection strategy tocontrol the switch unit to switch off, such that the power adapter stopscharging the battery, thus realizing the high protection of the batteryand improving the safety of charging.

Certainly, in another embodiment of the present disclosure, the terminalobtains the temperature of the first charging interface by performingthe bidirectional communication with the power adapter via the secondcharging interface. When the temperature of the first charging interfaceis greater than the predetermined protection temperature, the terminalcontrols the charging control switch to switch off, i.e., the chargingcontrol switch can be switched off at the terminal side, so as to stopthe charging process of the battery, thus ensuring the safety ofcharging.

During a process that the power adapter charges the terminal, the switchunit is controlled to switch off when the voltage sampling value isgreater than a second predetermined voltage value. Namely, adetermination is performed on the voltage sampling value during theprocess that the power adapter charges the terminal. When the voltagesampling value is greater than the second predetermined voltage value,it indicates that the voltage outputted by the power adapter is toohigh. At this time, the power adapter is controlled to stop charging theterminal by controlling the switch unit to switch off. In other words,the over-voltage protection of the power adapter is realized bycontrolling the switch unit to switch off, thus ensuring the safety ofcharging.

Certainly, in an embodiment of the present disclosure, the terminalobtains the voltage sampling value by performing a bidirectionalcommunication with the power adapter via the second charging interface,and controls to stop charging the battery when the voltage samplingvalue is greater than the second predetermined voltage value. Namely,the charging control switch is controlled to switch off at the terminalside, so as to stop the charging process, such that the safety ofcharging can be ensured.

In an embodiment of the present disclosure, during the process that thepower adapter charges the terminal, the switch unit is controlled toswitch off when the current sampling value is greater than apredetermined current value. In other words, during the process that thepower adapter charges the terminal, a determination is performed on thecurrent sampling value. When the current sampling value is greater thanthe predetermined current value, it indicates that the current outputtedby the power adapter is too high. At this time, the power adapter iscontrolled to stop charging the terminal by controlling the switch unitto switch off. In other words, the over-current protection of the poweradapter is realized by controlling the switch unit to switch off, thusensuring the safety of charging.

Similarly, the terminal obtains the current sampling value by performingthe bidirectional communication with the power adapter via the secondcharging interface, and controls to stop charging the battery when thecurrent sampling value is greater than the predetermined current value.In other words, the charging control switch is controlled to be switchedoff at the terminal side, such that the charging process of the batteryis stopped, thus ensuring the safety of charging.

The second predetermined voltage value and the predetermined currentvalue may be set according to actual situations.

In embodiments of the present disclosure, the status information of theterminal includes the electric quantity of the battery, the temperatureof the battery, the voltage/current of the battery of the terminal,interface information of the terminal and information on a pathimpedance of the terminal.

In detail, the power adapter can be coupled to the terminal via auniversal serial bus (USB) interface. The USB interface may be a generalUSB interface, or a micro USB interface. A data wire in the USBinterface is configured as the data wire in the first charginginterface, and configured for the bidirectional communication betweenthe power adapter and the terminal. The data wire may be D+ and/or D−wire in the USB interface. The bidirectional communication may refer toan information interaction performed between the power adapter and theterminal.

The power adapter performs the bidirectional communication with theterminal via the data wire in the USB interface, so as to determine tocharge the terminal in the second charging mode.

As an embodiment, when the power adapter performs the bidirectionalcommunication with the terminal via the first charging interface so asto determine to charge the terminal in the second charging mode, thepower adapter sends a first instruction to the terminal. The firstinstruction is configured to query the terminal whether to start thesecond charging mode. The power adapter receives a first replyinstruction from the terminal. The first reply instruction is configuredto indicate that the terminal agrees to start the second charging mode.

As an embodiment, before the power adapter sends the first instructionto the terminal, the power adapter charges the terminal in the firstcharging mode. When the power adapter determines that a chargingduration of the first charging mode is greater than a predeterminedthreshold, the power adapter sends the first instruction to theterminal.

It should be understood that, when the power adapter determines that acharging duration of the first charging mode is greater than apredetermined threshold, the power adapter may determine that theterminal has identified it as a power adapter, such that the fastcharging query communication may start.

As an embodiment, the power adapter is controlled to adjust a chargingcurrent to a charging current corresponding to the second charging modeby controlling the switch unit. Before the power adapter charges theterminal with the charging current corresponding to the second chargingmode, a bidirectional communication is performed with the terminal viathe first charging interface to determine a charging voltagecorresponding to the second charging mode, and the power adapter iscontrolled to adjust a charging voltage to the charging voltagecorresponding to the second charging mode.

As an embodiment, performing the bidirectional communication with theterminal via the first charging interface to determine the chargingvoltage corresponding to the second charging mode includes: sending bythe power adapter a second instruction to the terminal, receiving by thepower adapter a second reply instruction sent from the terminal, anddetermining by the power adapter the charging voltage corresponding tothe second charging mode according to the second reply instruction. Thesecond instruction is configured to query whether a current outputvoltage of the power adapter is suitable for being used as the chargingvoltage corresponding to the second charging mode. The second replyinstruction is configured to indicate that the current output voltage ofthe power adapter is suitable, high or low.

As an embodiment, before controlling the power adapter to adjust thecharging current to the charging current corresponding to the secondcharging mode, the charging current corresponding to the second chargingmode is determined by performing the bidirectional communication withthe terminal via the first charging interface.

As an embodiment, determining the charging current corresponding to thesecond charging mode by performing the bidirectional communication withthe terminal via the first charging interface includes: sending by thepower adapter a third instruction to the terminal, receiving by thepower adapter a third reply instruction sent from the terminal anddetermining by the power adapter the charging current corresponding tothe second charging mode according to the third reply instruction. Thethird instruction is configured to query a maximum charging currentsupported by the terminal. The third reply instruction is configured toindicate the maximum charging current supported by the terminal.

The power adapter may determine the above maximum charging current asthe charging current corresponding to the second charging mode, or mayset the charging current as a charging current less than the maximumcharging current.

As an embodiment, during the process that the power adapter charges theterminal in the second charging mode, the bidirectional communication isperformed with the terminal via the first charging interface, so as tocontinuously adjust a charging current outputted to the battery from thepower adapter by controlling the switch unit.

The power adapter may query the status information of the terminalcontinuously, so as to adjust the charging current continuously, forexample, query the voltage of the battery of the terminal, the electricquantity of the battery, etc.

As an embodiment, performing the bidirectional communication with theterminal via the first charging interface to continuously adjust thecharging current outputted to the battery from the power adapter bycontrolling the switch unit includes: sending by the power adapter afourth instruction to the terminal, receiving by the power adapter afourth reply instruction sent by the terminal, and adjusting thecharging current by controlling the switch unit according to the currentvoltage of the battery. The fourth instruction is configured to query acurrent voltage of the battery in the terminal. The fourth replyinstruction is configured to indicate the current voltage of the batteryin the terminal.

As an embodiment, adjusting the charging current by controlling theswitch unit according to the current voltage of the battery includes:adjusting the charging current outputted to the battery from the poweradapter to a charging current value corresponding to the current voltageof the battery by controlling the switch unit according to the currentvoltage of the battery and a predetermined correspondence betweenbattery voltage values and charging current values.

In detail, the power adapter may store the correspondence betweenbattery voltage values and charging current values in advance.

As an embodiment, during the process that the power adapter charges theterminal in the second charging mode, it is determined whether there isa poor contact between the first charging interface and the secondcharging interface by performing the bidirectional communication withthe terminal via the first charging interface. When it is determinedthat there is the poor contact between the first charging interface andthe second charging interface, the power adapter is controlled to quitthe second charging mode.

As an embodiment, before determining whether there is the poor contactbetween the first charging interface and the second charging interface,the power adapter receives information indicating a path impedance ofthe terminal from the terminal. The power adapter sends a fourthinstruction to the terminal. The fourth instruction is configured toquery a current voltage of the battery in the terminal. The poweradapter receives a fourth reply instruction sent by the terminal. Thefourth reply instruction is configured to indicate the current voltageof the battery in the terminal. The power adapter determines a pathimpedance from the power adapter to the battery according to an outputvoltage of the power adapter and the current voltage of the battery anddetermines whether there is the poor contact between the first charginginterface and the second charging interface according to the pathimpedance from the power adapter to the battery, the path impedance ofthe terminal, and a path impedance of a charging wire between the poweradapter and the terminal.

As an embodiment, before the power adapter is controlled to quit thesecond charging mode, a fifth instruction is sent to the terminal. Thefifth instruction is configured to indicate that there is the poorcontact between the first charging interface and the second charginginterface.

After sending the fifth instruction, the power adapter may quit thesecond charging mode or reset.

The fast charging process according to embodiments of the presentdisclosure is described from the perspective of the power adapter, andthen the fast charging process according to embodiments of the presentdisclosure will be described from the perspective of the terminal in thefollowing.

In embodiments of the present disclosure, the terminal supports thefirst charging mode and the second charging mode. The charging currentof the second charging mode is greater than that of the first chargingmode. The terminal performs the bidirectional communication with thepower adapter via the second charging interface such that the poweradapter determines to charge the terminal in the second charging mode.The power adapter outputs according to a charging current correspondingto the second charging mode, for charging the battery in the terminal.

As an embodiment, performing by the terminal the bidirectionalcommunication with the power adapter via the second charging interfacesuch that the power adapter determines to charge the terminal in thesecond charging mode includes: receiving by the terminal the firstinstruction sent by the power adapter, in which the first instruction isconfigured to query the terminal whether to start the second chargingmode; sending by the terminal a first reply instruction to the poweradapter. The first reply instruction is configured to indicate that theterminal agrees to start the second charging mode.

As an embodiment, before the terminal receives the first instructionsent by the power adapter, the battery in the terminal is charged by thepower adapter in the first charging mode. When the power adapterdetermines that a charging duration of the first charging mode isgreater than a predetermined threshold, the terminal receives the firstinstruction sent by the power adapter.

As an embodiment, before the power adapter outputs according to thecharging current corresponding to the second charging mode for chargingthe battery in the terminal, the terminal performs the bidirectionalcommunication with the power adapter via the second charging interface,such that the power adapter determines the charging voltagecorresponding to the second charging mode.

As an embodiment, performing by the terminal the bidirectionalcommunication with the power adapter via the second charging interfacesuch that the power adapter determines the charging voltagecorresponding to the second charging mode includes: receiving by theterminal a second instruction sent by the power adapter, and sending bythe terminal a second reply instruction to the power adapter. The secondinstruction is configured to query whether a current output voltage ofthe power adapter is suitable for being used as the charging voltagecorresponding to the second charging mode. The second reply instructionis configured to indicate that the current output voltage of the poweradapter is suitable, high or low.

As an embodiment, before the terminal receives the charging currentcorresponding to the second charging mode from the power adapter forcharging the battery in the terminal, the terminal performs thebidirectional communication with the power adapter via the secondcharging interface, such that the power adapter determines the chargingcurrent corresponding to the second charging mode.

Performing by the terminal the bidirectional communication with thepower adapter via the second charging interface such that the poweradapter determines the charging current corresponding to the secondcharging mode includes: receiving by the terminal a third instructionsent by the power adapter, in which the third instruction is configuredto query a maximum charging current supported by the terminal; sendingby the terminal a third reply instruction to the power adapter, in whichthe third reply instruction is configured to indicate the maximumcharging current supported by the terminal, such that the power adapterdetermines the charging current corresponding to the second chargingmode according to the maximum charging current.

As an embodiment, during a process that the power adapter charges theterminal in the second charging mode, the terminal performs thebidirectional communication with the power adapter via the secondcharging interface, such that the power adapter continuously adjusts acharging current outputted to the battery.

Performing by the terminal the bidirectional communication with thepower adapter via the second charging interface such that the poweradapter continuously adjusts a charging current outputted to the batteryincludes: receiving by the terminal a fourth instruction sent by thepower adapter, in which the fourth instruction is configured to query acurrent voltage of the battery in the terminal; sending by the terminala fourth reply instruction to the power adapter, in which the fourthreply instruction is configured to indicate the current voltage of thebattery in the terminal, such that the power adapter continuouslyadjusts the charging current outputted to the battery according to thecurrent voltage of the battery.

As an embodiment, during the process that the power adapter charges theterminal in the second charging mode, the terminal performs thebidirectional communication with the control unit, such that the poweradapter determines whether there is a poor contact between the firstcharging interface and the second charging interface.

Performing by the terminal the bidirectional communication with thepower adapter, such that the power adapter determines whether there isthe poor contact between the first charging interface and the secondcharging interface includes: receiving by the terminal a fourthinstruction sent by the power adapter, in which the fourth instructionis configured to query a current voltage of the battery in the terminal;sending by the terminal a fourth reply instruction to the power adapter,in which the fourth reply instruction is configured to indicate thecurrent voltage of the battery in the terminal, such that the poweradapter determines whether there is the poor contact between the firstcharging interface and the second charging interface according to anoutput voltage of the power adapter and the current voltage of thebattery.

As an embodiment, the terminal receives a fifth instruction sent by thepower adapter. The fifth instruction is configured to indicate thatthere is the poor contact between the first charging interface and thesecond charging interface.

In order to initiate and adopt the second charging mode, the poweradapter may perform a fast charging communication procedure with theterminal, for example, by one or more handshakes, so as to realize thefast charging of battery. Referring to FIG. 6, the fast chargingcommunication procedure according to embodiments of the presentdisclosure and respective stages in the fast charging process will bedescribed in detail. It should be understood that, communication actionsor operations illustrated in FIG. 6 are merely exemplary. Otheroperations or various modifications of respective operations in FIG. 6can be implemented in embodiments of the present disclosure. Inaddition, respective stages in FIG. 6 may be executed in an orderdifferent from that illustrated in FIG. 6, and it is unnecessary toexecute all the operations illustrated in FIG. 6. It should be notedthat, a curve in FIG. 6 represents a variation trend of a peak value ora mean value of the charging current, rather than a curve of actualcharging current.

In conclusion, with the charging method according to embodiments of thepresent disclosure, the power adapter is controlled to output the secondalternating current which meets the charging requirement, and the secondalternating current outputted by the power adapter is directly appliedto the battery of the terminal, thus realizing fast charging to thebattery directly by the output voltage/current with alternating currentwaveform, and realizing a closed-loop control on the output of the poweradapter by sampling the auxiliary winding to ensure that the secondalternating current meets the charging requirement. In contrast to theconventional constant voltage and constant current, a magnitude of theoutput voltage/current with alternating current waveform changesperiodically and an absolute value of a peak voltage of a positive halfof each cycle is greater than that of a trough voltage of a negativehalf of the cycle, such that a lithium precipitation of the lithiumbattery may be reduced, the service life of the battery may be improved,and a probability and intensity of arc discharge of a contact of acharging interface may be reduced, the service life of the charginginterface may be prolonged, and it is beneficial to reduce polarizationeffect of the battery, improve charging speed, and decrease heat emittedby the battery, thus ensuring a reliability and safety of the terminalduring the charging. Moreover, since the power adapter outputs thevoltage with the alternating current waveform, it is unnecessary toprovide an electrolytic condenser in the power adapter, which not onlyrealizes simplification and miniaturization of the power adapter, butalso decreases cost greatly.

As illustrated in FIG. 15, a charging device 1000 according toembodiments of the present disclosure includes a charging receivingterminal 1001, a voltage adjusting circuit 1002 and a central controlmodule 1003.

The charging receiving terminal 1001 is configured to receive a firstalternating current. An input end of the voltage adjusting circuit 1002is coupled to the charging receiving terminal 1001. An output end of thevoltage adjusting circuit 1002 is coupled to a battery (such as abattery 202 in a terminal). The voltage adjusting circuit 1002 isconfigured to adjust the first alternating current to output a secondalternating current, and to directly apply the second alternatingcurrent to the battery for charging the battery. For each cycle of thesecond alternating current, an absolute value of a peak voltage of apositive half is greater than that of a trough voltage of a negativehalf. The central control module 1003 is configured to control thevoltage adjusting circuit 1002 to adjust voltage and/or current of thesecond alternating current, so as to respond the charging requirement ofthe battery.

According to an embodiment of the present disclosure, a peak voltage ofthe second alternating current is less than a peak voltage of thealternating current from mains supply, and a period of the secondalternating current is greater than that of the alternating current frommains supply.

According to an embodiment of the present disclosure, as illustrated inFIG. 16, the charging device 1000 may be arranged in the power adapter1.

According to an embodiment of the present disclosure, as illustrated inFIG. 17, the charging device 1000 may also be arranged in the terminal2.

With the charging device according to embodiments of the presentdisclosure, by adjusting the alternating current from mains supply, thesecond alternating current which meets the charging requirement of thebattery can be outputted and directly applied to the battery forperforming a fast charging on the battery. In contrast to theconventional constant voltage and constant current, a lithiumprecipitation of the lithium battery may be reduced, the service life ofthe battery may be improved, and a probability and intensity of arcdischarge of a contact of a charging interface may be reduced, theservice life of the charging interface may be prolonged, and it isbeneficial to reduce polarization effect of the battery, improvecharging speed, and decrease heat emitted by the battery, thus ensuringa reliability and safety of the terminal during the charging.

Moreover, embodiments of the present disclosure also provide a chargingmethod. The charging method includes: receiving a first alternatingcurrent from mains supply; adjusting the first alternating current frommains supply to output a second alternating current; applying the secondalternating current to a battery directly to charge the battery, inwhich, for each cycle of the second alternating current, an absolutevalue of a peak voltage of a positive half is greater than that of atrough voltage of a negative half; adjusting voltage and/or current ofthe second alternating current in response to the charging requirementof the battery.

According to an embodiment of the present disclosure, a peak voltage ofthe second alternating current is less than a peak voltage of thealternating current from mains supply, and a period of the secondalternating current is greater than that of the alternating current frommains supply.

With the charging method according to embodiments of the presentdisclosure, by adjusting the alternating current, the second alternatingcurrent which meets the charging requirement of the battery can beoutputted and directly applied to the battery for performing a fastcharging on the battery. In contrast to the conventional constantvoltage and constant current, a lithium precipitation of the lithiumbattery may be reduced, the service life of the battery may be improved,and a probability and intensity of arc discharge of a contact of acharging interface may be reduced, the service life of the charginginterface may be prolonged, and it is beneficial to reduce polarizationeffect of the battery, improve charging speed, and decrease heat emittedby the battery, thus ensuring a reliability and safety of the terminalduring the charging.

In at least one embodiment of the present disclosure, part or allstructure (hardware and software) of the adapter can be integrated intothe terminal. Integrated structure of the adapter and the terminal canbe called as the charging system of the present disclosure, or called asa terminal.

In the specification of the present disclosure, it is to be understoodthat terms such as “central,” “longitudinal,” “lateral,” “length,”“width,” “thickness,” “upper,” “lower,” “front,” “rear,” “left,”“right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” “outer,”“clockwise,” “counterclockwise,” “axial,” “radial,” and “circumference”refer to the orientations and location relations which are theorientations and location relations illustrated in the drawings, and fordescribing the present disclosure and for describing in simple, andwhich are not intended to indicate or imply that the device or theelements are disposed to locate at the specific directions or arestructured and performed in the specific directions, which could not tobe understood to the limitation of the present disclosure.

In addition, terms such as “first” and “second” are used herein forpurposes of description and are not intended to indicate or implyrelative importance or significance or to imply the number of indicatedtechnical features. Thus, the feature defined with “first” and “second”may comprise one or more of this feature. In the description of thepresent disclosure, “a plurality of” means two or more than two, unlessspecified otherwise.

In the present disclosure, unless specified or limited otherwise, theterms “mounted,” “connected,” “coupled,” “fixed” and the like are usedbroadly, and may be, for example, fixed connections, detachableconnections, or integral connections; may also be mechanical orelectrical connections; may also be direct connections or indirectconnections via intervening structures; may also be inner communicationsof two elements, which can be understood by those skilled in the artaccording to specific situations.

In the present disclosure, unless specified or limited otherwise, astructure in which a first feature is “on” or “below” a second featuremay include an embodiment in which the first feature is in directcontact with the second feature, and may also include an embodiment inwhich the first feature and the second feature are not in direct contactwith each other, but are contacted via an additional feature formedtherebetween. Furthermore, a first feature “on,” “above,” or “on top of”a second feature may include an embodiment in which the first feature isright or obliquely “on,” “above,” or “on top of” the second feature, orjust means that the first feature is at a height higher than that of thesecond feature; while a first feature “below,” “under,” or “on bottomof” a second feature may include an embodiment in which the firstfeature is right or obliquely “below,” “under,” or “on bottom of” thesecond feature, or just means that the first feature is at a heightlower than that of the second feature.

Reference throughout this specification to “an embodiment,” “someembodiments,” “one embodiment”, “another example,” “an example,” “aspecific example,” or “some examples,” means that a particular feature,structure, material, or characteristic described in connection with theembodiment or example is included in at least one embodiment or exampleof the present disclosure. Thus, the appearances of the phrases such as“in some embodiments,” “in one embodiment”, “in an embodiment”, “inanother example,” “in an example,” “in a specific example,” or “in someexamples,” in various places throughout this specification are notnecessarily referring to the same embodiment or example of the presentdisclosure. Furthermore, the particular features, structures, materials,or characteristics may be combined in any suitable manner in one or moreembodiments or examples.

Those skilled in the art may be aware that, in combination with theexamples described in the embodiments disclosed in this specification,units and algorithm steps can be implemented by electronic hardware, ora combination of computer software and electronic hardware. In order toclearly illustrate interchangeability of the hardware and software,components and steps of each example are already described in thedescription according to the function commonalities. Whether thefunctions are executed by hardware or software depends on particularapplications and design constraint conditions of the technicalsolutions. Persons skilled in the art may use different methods toimplement the described functions for each particular application, butit should not be considered that the implementation goes beyond thescope of the present disclosure.

Those skilled in the art may be aware that, with respect to the workingprocess of the system, the device and the unit, reference is made to thepart of description of the method embodiment for simple and convenience,which are described herein.

In embodiments of the present disclosure, it should be understood that,the disclosed system, device and method may be implemented in other way.For example, embodiments of the described device are merely exemplary.The partition of units is merely a logical function partitioning. Theremay be other partitioning ways in practice. For example, several unitsor components may be integrated into another system, or some featuresmay be ignored or not implemented. Further, the coupling between eachother or directly coupling or communication connection may beimplemented via some interfaces. The indirect coupling or communicationconnection may be implemented in an electrical, mechanical or othermanner.

In embodiments of the present disclosure, it should be understood that,the units illustrated as separate components can be or not be separatedphysically, and components described as units can be or not be physicalunits, i.e., can be located at one place, or can be distributed ontomultiple network units. It is possible to select some or all of theunits according to actual needs, for realizing the objective ofembodiments of the present disclosure.

In addition, each functional unit in the present disclosure may beintegrated in one progressing module, or each functional unit exists asan independent unit, or two or more functional units may be integratedin one module.

If the integrated module is embodied in software and sold or used as anindependent product, it can be stored in the computer readable storagemedium. Based on this, the technical solution of the present disclosureor a part making a contribution to the related art or a part of thetechnical solution may be embodied in a manner of software product. Thecomputer software produce is stored in a storage medium, including someinstructions for causing one computer device (such as a personal PC, aserver, or a network device etc.) to execute all or some of steps of themethod according to embodiments of the present disclosure. Theabove-mentioned storage medium may be a medium able to store programcodes, such as, USB flash disk, mobile hard disk drive (mobile HDD),read-only memory (ROM), random-access memory (RAM), a magnetic tape, afloppy disc, an optical data storage device, and the like.

Although explanatory embodiments have been illustrated and described, itwould be appreciated by those skilled in the art that the aboveembodiments cannot be construed to limit the present disclosure, andchanges, alternatives, and modifications can be made in the embodimentswithout departing from spirit, principles and scope of the presentdisclosure.

What is claimed is:
 1. A power adapter, comprising: a first rectifier,configured to rectify an input alternating current and to output avoltage with a first pulsating waveform; a switch unit, configured tomodulate the voltage with the first pulsating waveform according to acontrol signal; a transformer, having a primary winding, a plurality ofsecondary windings and an auxiliary winding, wherein the transformer isconfigured to output a plurality of voltages with pulsating waveformsvia the plurality of secondary windings according to the modulatedvoltage with the first pulsating waveform, and to couple the modulatedvoltage with the first pulsating waveform via the auxiliary winding; asynthesizing unit, configured to synthesize the plurality of voltageswith the pulsating waveforms to output a second alternating current,wherein for each cycle of the second alternating current, an absolutevalue of a peak voltage of a positive half of the second alternatingcurrent is greater than that of a trough voltage of a negative half ofthe second alternating current; a first charging interface, coupled toan output end of the synthesizing unit, and configured to apply thesecond alternating current to a battery in a terminal via a secondcharging interface of the terminal when the first charging interface iscoupled to the second charging interface, in which the second charginginterface is coupled to the battery; a sampling unit, configured tosample a voltage and/or a current at the auxiliary winding to obtain avoltage sampling value and/or a current sampling value; and a controlunit, coupled to the sampling unit and the switch unit respectively, andconfigured to output the control signal to the switch unit, and toadjust a duty ratio of the control signal according to the currentsampling value and/or the voltage sampling value, such that the secondalternating current meets a charging requirement of the terminal.
 2. Thepower adapter according to claim 1, wherein the plurality of secondarywindings comprises a first secondary winding and a second secondarywinding, a first end of the primary winding is coupled to a first outputend of the first rectifier, a second end of the primary winding iscoupled to the switch unit, the first secondary winding and the secondsecondary winding are coupled to the synthesizing unit respectively, andthe transformer is configured to output a voltage with a secondpulsating waveform via the first secondary winding according to themodulated voltage with the first pulsating waveform, and to output avoltage with a third pulsating waveform via the second secondary windingaccording to the modulated voltage with the first pulsating waveform. 3.The power adapter according to claim 2, wherein the synthesizing unit isconfigured to synthesize the voltage with the second pulsating waveformand the voltage with the third pulsating waveform to output the secondalternating current.
 4. The power adapter according to claim 1, whereinthe control unit is further configured to adjust a frequency of thecontrol signal according to the voltage sampling value and/or thecurrent sampling value.
 5. The power adapter according to claim 1,wherein the control unit is further configured to communicate with theterminal so as to obtain status information of the terminal, and thecontrol unit is further configured to adjust the duty ratio of thecontrol signal according to the status information of the terminal andat least one of the voltage sampling value and the current samplingvalue.
 6. The power adapter according to claim 1, further comprising: adriving unit, coupled between the switch unit and the control unit, andconfigured to drive the switch unit to switch on or off according to thecontrol signal.
 7. The power adapter according to claim 6, furthercomprises: an isolation unit, coupled between the driving unit and thecontrol unit.
 8. The power adapter according to claim 6, furthercomprises: a power supply unit, coupled to the auxiliary winding,wherein the auxiliary winding is configured to output a voltage with afourth pulsating waveform, and the power supply unit is configured toconvert the voltage with the fourth pulsating waveform and to output afirst direct current, so as to supply power to the driving unit and/orthe control unit respectively.
 9. The power adapter according to claim8, wherein the sampling unit is configured to sample a voltage and/or acurrent of the voltage with the fourth pulsating waveform to obtain thevoltage sampling value and/or the current sampling value.
 10. The poweradapter according to claim 1, wherein a working frequency of thetransformer ranges from 50 KHz to 2 MHz.
 11. The power adapter accordingto claim 1, wherein the sampling unit comprises: a first currentsampling circuit, configured to sample the current at the auxiliarywinding so as to obtain the current sampling value; and a first voltagesampling circuit, configured to sample the voltage at the auxiliarywinding so as to obtain the voltage sampling value.
 12. The poweradapter according to claim 11, wherein the first voltage samplingcircuit comprises: a peak voltage sampling and holding unit, configuredto sample and hold a peak voltage of the fourth voltage; a cross-zerosampling unit, configured to sample a zero crossing point of the fourthvoltage; a bleeder unit, configured to drain off the peak voltagesampling and holding unit at the zero crossing point; and an AD samplingunit, configured to sample the peak voltage in the peak voltage samplingand holding unit so as to obtain the voltage sampling value.
 13. Thepower adapter according to claim 1, further comprising: a second voltagesampling circuit, configured to sample the voltage with the firstpulsating waveform, and coupled to the control unit, wherein the controlunit is configured to control the switch unit to switch on for a firstpredetermined time period for discharging when a voltage value sampledby the second voltage sampling circuit is greater than a firstpredetermined voltage value.
 14. The power adapter according to claim 1,wherein the control unit is configured to communicate with the terminalvia the first charging interface to determine a charging mode, in whichthe charging mode comprises a first charging mode and a second chargingmode.
 15. The power adapter according to claim 14, further comprising: arectifying and filtering unit, configured to perform a rectifying andfiltering on one of the plurality of voltages with the pulsatingwaveforms to output a second direct current; and a controllable switch,configured to control an operation of the rectifying and filtering unit;wherein the control unit is further configured to control the rectifyingand filtering unit to perform the rectifying and filtering on one of theplurality of voltages with the pulsating waveforms and control thesynthesizing unit to stop from synthesizing the voltage with the secondpulsating waveform and the voltage with the third pulsating waveform bycontrolling the controllable switch when determining the charging modeis the first charging mode, such that the rectifying and filtering unitoutputs the second direct current to charge the battery; and to controlthe rectifying and filtering unit to stop from performing the rectifyingand filtering on one of the plurality of voltages with the pulsatingwaveforms and control the synthesizing unit to synthesize the voltagewith the second pulsating waveform and the voltage with the thirdpulsating waveform by controlling the controllable switch whendetermining the charging mode as the second charging mode, such that thesecond alternating current is applied to the battery.
 16. The poweradapter according to claim 14, wherein the control unit is furtherconfigured to obtain a charging current and/or a charging voltagecorresponding to the second charging mode according to statusinformation of the terminal and to adjust the duty ratio of the controlsignal according to the charging current and/or the charging voltagecorresponding to the second charging mode, when determining the chargingmode as the second charging mode.
 17. The power adapter according toclaim 16, wherein the status information of the terminal comprises atemperature of the battery, wherein when the temperature of the batteryis greater than a first predetermined temperature threshold or thetemperature of the battery is less than a second predeterminedtemperature threshold, the second charging mode is switched to the firstcharging mode when a current charging mode is the second charging mode,in which the first predetermined temperature threshold is greater thanthe second predetermined temperature threshold.
 18. The power adapteraccording to claim 17, wherein the control unit is further configured tocontrol the switch unit to switch off when the temperature of thebattery is greater than a predetermined high temperature protectionthreshold, or the control unit is further configured to control theswitch unit to switch off when the voltage sampling value is greaterthan a second predetermined voltage value, or the control unit isfurther configured to control the switch unit to switch off when thecurrent sampling value is greater than a predetermined current value.19. A charging system for a terminal, comprising: a power adapter,comprising: a first rectifier, configured to rectify an inputalternating current and to output a voltage with a first pulsatingwaveform; a switch unit, configured to modulate the voltage with thefirst pulsating waveform according to a control signal; a transformer,having a primary winding, a plurality of secondary windings and anauxiliary winding, wherein the transformer is configured to output aplurality of voltages with pulsating waveforms via the plurality ofsecondary windings according to the modulated voltage with the firstpulsating waveform, and to couple the modulated voltage with the firstpulsating waveform via the auxiliary winding; a synthesizing unit,configured to synthesize the plurality of voltages with the pulsatingwaveforms to output a second alternating current, wherein for each cycleof the second alternating current, an absolute value of a peak voltageof a positive half of the second alternating current is greater thanthat of a trough voltage of a negative half of the second alternatingcurrent; a first charging interface, coupled to an output end of thesynthesizing unit; a sampling unit, configured to sample a voltageand/or a current at the auxiliary winding to obtain a voltage samplingvalue and/or a current sampling value; and a control unit, coupled tothe sampling unit and the switch unit respectively, and configured tooutput the control signal to the switch unit, and to adjust a duty ratioof the control signal according to the current sampling value and/or thevoltage sampling value, such that the second alternating current meets acharging requirement of the terminal, and the terminal, comprising asecond charging interface and a battery, the second charging interfacebeing coupled to the battery, wherein the second charging interface isconfigured to apply the second alternating current to the battery whenthe second charging interface is coupled to the first charginginterface.
 20. A charging method for a terminal, comprising: when afirst charging interface of a power adapter is coupled with a secondcharging interface of the terminal, performing a first rectification onan input alternating current to output a voltage with a first pulsatingwaveform; modulating the voltage with the first pulsating waveform bycontrolling a switch unit, and outputting a plurality of voltages withpulsating waveforms by a conversion of a transformer; synthesizing theplurality of voltages with the pulsating waveforms to output a secondalternating current, wherein for each cycle of the second alternatingcurrent, an absolute value of a peak voltage of a positive half of thesecond alternating current is greater than that of a trough voltage of anegative half of the second alternating current; applying the secondalternating current to a battery of the terminal via the second charginginterface; coupling a primary output of the transformer via an auxiliarywinding of the transformer, and sampling a voltage and/or a current atthe auxiliary winding to obtain a voltage sampling value and/or acurrent sampling value; and adjusting a duty ratio of a control signalfor controlling the switch unit according to the voltage sampling valueand/or the current sampling value, such that the second alternatingcurrent meets a charging requirement.